Every commercial relationship in Australia rests on an agreement, but the law does not require that agreement to look like a formal document. A deal can be struck with a signed contract, a phone call, a string of emails, a click on a website, or even the way the parties behave toward each other. Australian law recognises all of these as valid ways of forming a contract that a court will enforce.
The method matters because it decides what you can prove if the deal goes wrong, what formalities apply, and how long you have to enforce the agreement. This guide covers the common elements every binding agreement needs, the six main methods of forming a contract in Australia, the situations where the law chooses the method for you, and the compliance obligations that follow the deal rather than the form.
Who has a stake in how your agreement is formed
Before the methods, it helps to map the players, because each has a different interest in how your agreement comes into existence:
- Your business and the counterparty: You negotiate the terms and choose the method, and you are the ones who must be able to show what was agreed if a dispute arises.
- A court or tribunal: If the relationship breaks down, a court decides whether an agreement exists, what its terms are, and whether it is enforceable, applying the common law and any legislation that bears on the deal.
- Regulators: The ACCC polices the Australian Consumer Law and the franchising code, the Fair Work Ombudsman oversees employment standards, and the Office of the Australian Information Commissioner enforces privacy law. Each can act against a business regardless of how its contracts were formed.
- A lawyer: A practitioner drafts and reviews the documents, makes sure they are executed properly, and steps in when proof of an agreement becomes the issue.
The five elements every binding agreement needs
Whatever method you use, Australian common law requires the same five elements before a contract is enforceable. They are the baseline every method below must satisfy:
- Offer: One party proposes terms, such as a quote or proposal capable of immediate acceptance.
- Acceptance: The other party agrees to those terms without introducing new conditions; a reply that changes the terms is generally a counter-offer, not an acceptance.
- Consideration: Each side gives something of value: money, goods, services, or a promise. A promise with nothing exchanged for it is generally not enforceable.
- Intention to create legal relations: Both parties must intend the agreement to be legally binding. The High Court confirmed in Ermogenous v Greek Orthodox Community of SA Inc (2002) 209 CLR 95 that this intention is assessed objectively from what the parties said and did, rather than by rigid presumption.
- Certainty: The key terms must be sufficiently complete and clear to enforce. The High Court in Upper Hunter County District Council v Australian Chilling & Freezing Co Ltd (1968) 118 CLR 429 explained that courts lean against holding an agreement void for uncertainty, but there must be enough substance to give the terms meaning.
These elements are about substance, not form, which is why a verbal deal can bind as effectively as a signed document. The methods differ in how easily the existence and terms of the agreement can be proven, and what formalities attach to each.
The six methods of forming a contract
Australian law recognises six main ways a contract can come into existence. In practice most businesses use a mixture of them depending on the value, complexity, and risk of the deal.
Written contracts signed by hand or electronically
A written contract is the most secure method because the terms are recorded and both parties signal consent by signing. It is the sensible choice for arrangements that are complex, long term, high value, or that involve intellectual property, because it fixes scope, price, and risk allocation in a form a court can read directly.
Signing does not have to mean pen on paper. Under s 10 of the Electronic Transactions Act 1999 (Cth), a signature requirement under a Commonwealth law is satisfied by an electronic method that identifies the person and indicates their intention, provided the method is as reliable as appropriate in the circumstances. Each state and territory has a matching law for state-based requirements. That is why typing a name into a document sent by email, or clicking to sign through an e-signature platform, is generally a valid signature in Australia.
For companies, the signing mechanics are set by s 127 of the Corporations Act 2001 (Cth). A company executes a document without a common seal if it is signed by two directors, or a director and a company secretary, or, for a proprietary company with a sole director who is also the sole secretary or who has no secretary, by that director alone. The Corporations Act 2001 (Cth) expressly allows the signing requirement to be satisfied electronically. Anyone dealing with a company can rely on assumptions about the authority of these officeholders, which is one reason proper execution blocks matter.
Verbal agreements
A verbal agreement can be fully binding if the five elements are present. Agreeing to a price and a delivery date over the phone, or at a meeting, is a contract in the same way a signed document is. The difference is proof. If the deal sours, you must convince a court that an agreement existed and what its terms were, usually from your word against theirs.
The practical fix is a short follow-up email: "to confirm our call, we agreed you will supply X for $Y, delivered by Z." That email is written evidence of the agreement, and if the other party proceeds without objecting, it becomes very hard for them to later deny the terms. For anything beyond simple, low-risk transactions, a written confirmation is second best to a signed contract, but far better than nothing.
Contracts implied by conduct
Sometimes the parties never say or write anything, but their actions show an agreement. Ordering a coffee and drinking it implies an obligation to pay. Sending a purchase order and having it filled implies agreement on the terms of supply. These are contracts implied by conduct, and they are enforceable.
The weakness is scope: when nothing is recorded, parties disagree about quality standards, warranties, or delivery obligations. Conduct-based contracts suit routine, low-value dealings where the terms are obvious; where detail matters, relying on implication alone invites trouble.
Online agreements: clickwrap and browsewrap
Most online businesses form contracts through their websites or apps when a user ticks a box or clicks "I agree". These clickwrap agreements are contracts like any other, and the Electronic Transactions Act 1999 (Cth) contains specific rules for them. Under s 15B of the Act, a proposal made through electronic communications that is not addressed to specific parties, such as the content of a public website, is treated as an invitation to treat rather than an offer, unless it clearly indicates an intention to be bound. That means the customer's order or sign-up is the offer, and your terms are accepted when you confirm or supply.
The Act also protects against input errors. Section 15D lets a person who makes an error in an electronic communication with an automated system, such as an order form, withdraw the affected communication if the system gave no chance to correct the error, they notify the other party promptly, and they have not benefited from the goods or services. Businesses building online checkouts should be aware this right exists.
The enforcement risk is notice. Terms buried at the bottom of a page, presented only after payment, or requiring a scroll through pages of fine print may not form part of the contract. The safer design is a positive step: an unchecked box that must be ticked, with the terms linked and accessible before acceptance, and a stored record of what the customer saw and agreed to. So-called browsewrap, where a business claims mere use of the site constitutes acceptance of terms the user never saw, is the weakest version of this method and frequently fails.
Contracts formed by email
A deal can be concluded entirely by email where the chain shows an offer and an acceptance. A supplier quoting a price and scope, and a customer replying "yes, go ahead," have a contract even if nothing is formally signed. The difficulty is that informal language and scattered threads create ambiguity: which version of the price list applied, whether the reply was conditional, or whether an earlier email was superseded.
The simple fix is a final confirmation email that consolidates the deal: "we will deliver X by Y for $Z, subject to the attached terms; please confirm this is correct." If the other party confirms, the terms are fixed. Businesses that regularly contract by email should consider a short template of terms they can attach to the confirmation, so the informal chain does not have to carry the whole deal.
Deeds
A deed is a special category of written agreement with its own formalities. Its distinctive feature is that it does not require consideration, so it can be used for gratuitous promises, releases, and waivers where nothing is exchanged. Deeds are commonly used for deeds of release, deeds of confidentiality, and deed polls for one-sided commitments.
To be valid, a deed must be in writing, signed, and delivered, and in most states witnessed or attested. The old requirement of a physical seal has largely been replaced by attestation, and for companies a seal is not needed at all. Under s 127 of the Corporations Act 2001 (Cth), a company executes a deed if the document is expressed to be executed as a deed and is signed in the way the section requires.
A deed also changes the time limits for enforcement. In New South Wales, s 16 of the Limitation Act 1969 (NSW) gives an action founded on a deed a limitation period of twelve years, compared with six years for a simple contract under s 14 of the same Act. Other states and territories have comparable, though not identical, rules. That longer window is one reason secured or long-term arrangements are sometimes documented as deeds.
When the law picks the method for you
For most deals you are free to choose the method. But in a handful of situations, legislation or a mandatory code requires writing, a signed document, or a particular form, and a verbal or implied deal will not do:
- Contracts for the sale of land: Every state requires a contract for the sale or disposition of an interest in land to be in writing, or evidenced by a signed memorandum, as a condition of enforceability. The equitable doctrine of part performance can rescue an oral land deal in limited circumstances, but no sensible business relies on it.
- Guarantees: A guarantee, where one person answers for the debt or default of another, must generally be in writing and signed by the guarantor to be enforceable.
- Franchise agreements: Franchising is regulated by the Franchising Code of Conduct, a mandatory industry code under the Competition and Consumer Act 2010 (Cth), policed by the ACCC. The code requires franchise agreements to be documented in writing and accompanied by disclosure documents setting out the terms of the arrangement. A new Franchising Code commenced on 1 April 2025, with some rules applying from 1 November 2025, so check the current code before entering or renewing a franchise.
- Company and trust documents: Documents such as share transfers and director appointments need to be executed in the way the governing legislation prescribes, often under s 127 of the Corporations Act 2001 (Cth), whether the document is a simple contract or a deed.
Compliance that follows the deal, not the form
Whatever method you use, a range of obligations attach to the deal itself. These apply even where the contract is verbal, implied, or online, and they are a common source of regulator action:
- Australian Consumer Law: If you supply goods or services, the Australian Consumer Law (ACL) in Schedule 2 of the Competition and Consumer Act 2010 (Cth) applies. Section 18 prohibits misleading or deceptive conduct in trade or commerce, and the consumer guarantees in Part 3-2 protect consumers who buy goods or services, regardless of what your written terms say. Terms that try to contract out of the guarantees are void.
- Unfair contract terms: Under s 23 of the ACL, an unfair term in a standard form consumer or small business contract is void, while the rest of the contract continues to operate if it can. A business that proposes or relies on an unfair term in a standard form contract can also face a pecuniary penalty. Terms that create a significant imbalance in the parties' rights and are not reasonably necessary to protect the business's legitimate interests are at risk, so standard terms deserve a periodic review.
- Employment law: An employment relationship exists even without a written contract, and the National Employment Standards in the Fair Work Act 2009 (Cth) apply to every employee regardless of the form of the agreement. Under s 125 of that Act, an employer must give each new employee the Fair Work Information Statement before or as soon as practicable after they start, and casual employees must receive the Casual Employment Information Statement under s 125A. Awards and enterprise agreements can add further requirements. A written employment contract does not replace these obligations; it sits alongside them.
- Privacy law: The Privacy Act 1988 (Cth) applies to most businesses with an annual turnover above $3 million, and to some smaller businesses in specific categories such as health service providers and businesses that trade in personal information. Under s 6D of the Act, a business is a small business for these purposes if its annual turnover for the previous financial year was $3 million or less. If the Act applies, your contracts and processes must line up with the Australian Privacy Principles, including how you collect, use, and disclose personal information.
Where agreements commonly come unstuck
Most contract disputes are not about the law of offer and acceptance. They are about the practical consequences of the method chosen:
- The wrong person signs: A document signed by someone without authority may not bind the company. Following the s 127 execution rules, and checking that the counterparty's signatory has authority, prevents this failure at the door.
- Variations made verbally: Agreeing to a change in scope or price over the phone, without recording it, is a common source of dispute. Confirm variations in writing, even by email, so the paper trail stays clear.
- Buried online terms: A clickwrap process that does not show the terms before acceptance, or that lets customers complete a purchase without positively agreeing, risks terms that are not part of the contract at all.
- Ambiguous email chains: Scattered threads and informal language make it hard to identify which terms applied. A single confirming email fixes the record.
- The clock running out: A limitation period is not a distant abstraction. For a simple contract in New South Wales the limit is six years; for a deed it is twelve. If the relationship breaks down late, the method you chose can determine whether you can still sue.
- Overreach in standard terms: A term that is unfair in a standard form contract is void under s 23 of the ACL, and proposing or relying on it can attract a penalty. The business that drafted it is the one at risk, not the customer.
When a lawyer earns their keep
A lawyer's value in this area is concentrated at two points: formation and dispute. At formation, a practitioner helps you choose the method that matches the risk of the deal, drafts or reviews the terms, builds correct execution blocks so the right people sign in the right way, and checks standard form contracts against the unfair contract terms regime and the consumer guarantees. For online businesses, a lawyer can review the acceptance flow so your clickwrap terms are actually incorporated. If a dispute later turns on whether an agreement existed, or what its terms were, that early work is what makes the difference.
Engaging a lawyer at formation is usually far cheaper than litigating a proof problem later. A free initial consultation can quickly establish which method your deal needs, whether your existing templates are exposed, and what the drafting or review would cost.
The method you choose decides what you can prove
The strongest theme running through this area of law is that the method of formation is really a decision about proof. A signed contract, a captured click, and a confirmed email all convert an agreement into evidence a court or regulator can read. A handshake, an unrecorded call, and a buried browsewrap link leave you arguing about whether there was ever a deal at all. The cost of clarity is smallest at the moment the agreement is made, and largest after expectations have diverged. Before you rely on any particular method, ask yourself how you would prove the terms in twelve months' time, and if the answer is not comfortable, get the agreement recorded and reviewed while it is still cheap to do so.