Contract Formation in Australia — The Essentials | Awelle

This article covers the elements required for a contract to come into existence — the point at which a contract becomes legally binding. It sets out drafting…

Lisa Muscatello's avatar

Lisa Muscatello

By the Awelle Legal Team — practising Australian lawyers.

Scope and application

This article covers the elements required for a contract to come into existence — the point at which a contract becomes legally binding. It sets out drafting steps to reduce the risk of a dispute about whether, and on what terms, a contract has been formed.

The note applies to contracts formed by any means recognised under Australian law, including written contracts, verbal agreements, contracts formed by conduct, and contracts formed electronically.

This note assumes Australian federal common law principles of general contract formation, which apply consistently across the states and territories, subject to state and territory legislation that governs formal requirements for particular contract types (for example, contracts for the sale of land).

Key legal principles

The elements required to form a contract

Under Australian law, an agreement becomes a legally binding contract only where the following elements are present. If any element is missing, there is no enforceable contract, regardless of what the parties believed or intended.

• Offer. A clear proposal by one party (the offeror) communicating definite terms that the other party can accept without further negotiation. An offer is distinct from an invitation to negotiate (such as the display of goods with a price tag or an advertisement, which merely invites the other party to make an offer to buy), and from a unilateral offer, which is an offer for an act in exchange for a promise (for example, a reward).
• Acceptance. Acceptance is when the offeree accepts an offer on the terms proposed by the offeror. Acceptance must be unconditional, must mirror the terms of the offer made by the offeror (the mirror image rule), and must be communicated to the offeror in the manner required or reasonably expected (such as in writing, verbally, or by conduct). A purported acceptance that introduces new or different terms is a counter-offer, and it extinguishes the original offer. Silence does not generally constitute acceptance unless the offer expressly permits it.
• Consideration. Consideration refers to when each party provides something of value — usually money, goods, services or promises — in exchange for the other party’s promise. Consideration may be given already or may be provided in future. Courts do not assess whether consideration is adequate or fair, only whether it has some value from a legal standpoint. Nominal consideration is sufficient. This requirement reflects the underlying bargain theory of contract: the parties must agree to an exchange of value in order to form a contract.
• Intention to create legal relations. The parties must objectively intend their agreement to be legally enforceable. Commercial agreements carry a general presumption of an intention to create legal relations, while arrangements that are social or with family carry the opposite presumption. In each case the presumption is rebuttable on the facts.

In addition to these core elements, a valid contract also requires:

• Certainty. The terms of the contract must be sufficiently clear and complete for a court to identify what has been agreed and to enforce it. Vague, incomplete, or open-ended terms risk a finding that no binding contract exists.
• Capacity. All parties must have legal capacity to enter the contract. Companies must enter into contracts through authorised representatives such as company directors. Minors generally lack capacity except for essential matters. Persons with impaired mental capacity and individuals who are significantly intoxicated may also lack capacity.
• Legality. A contract for an illegal purpose, that breaches legislation, or that is contrary to public policy (for example, an unreasonable restraint of trade) is void and unenforceable regardless of whether the other elements are satisfied.
• Genuine consent. A contract may be voidable, rather than void from the outset, where a party’s consent was affected by misrepresentation, mistake, duress, or undue influence. Parties should treat genuine consent as a topic distinct from formation and obtain separate guidance where a vitiating factor is in issue.

A recognised exception to the requirement for consideration is a deed. A deed does not require consideration provided it satisfies the formal requirements for a deed, including signature and, in most jurisdictions, witnessing and an intention that the document take effect as a deed. Deeds are commonly used where one party enters into a unilateral commitment. Examples include settlement deeds, declarations, non-disclosure deeds and powers of attorney.

Objective assessment of formation

Australian courts determine whether, when, and on what terms a contract was formed by reference to the objective conduct and words of the parties, not their private or subjective intentions. The test is what a reasonable person in the position of the parties would have understood from what was said and done.

A contract can be inferred from conduct alone, without any express words, but the courts have emphasised that this occurs rarely and only where the conduct, viewed in light of the surrounding circumstances, shows a tacit understanding or agreement sufficient to establish all the essential terms of an express contract.

When a contract becomes binding

A contract generally becomes binding at the moment of acceptance, when all the essential elements are present and the parties have reached complete agreement. This can occur through signature, through communicated acceptance by words or conduct, or upon satisfaction of a condition precedent (for example, a term making the contract subject to finance approval).

Where parties negotiate in stages or intend to record their agreement in a more formal document, the seminal analysis from Masters v Cameron (1954) 91 CLR 353 (and subsequent analyses by the courts) applies. Preliminary agreements generally fall into one of four categories:

1. the parties intend to be immediately bound, but to restate their agreement in a fuller or more precise form (not different in effect);
2. the parties have completely agreed on all terms of their bargain and intend no departure from the terms, but have made performance conditional upon the execution of a formal document, so that the effect of the term to execute a formal document may be to ‘place upon the parties an obligation, capable of being specifically enforced by the court, to sign a further contract in accordance with the informal agreement which they have already made’;
3. the parties do not intend to make a concluded bargain at all unless and until a final agreement is executed (no binding agreement arises); or
4. the parties intend to be immediately bound but also expect to make a further contract in substitution for the original, containing additional terms by consent.

Which category applies turns on the facts, in particular the language used and the surrounding commercial context.

The Full Federal Court’s decision in Cirrus Real Time Processing Systems Pty Ltd v Jet Aviation Australia Pty Ltd \[2025\] FCAFC 85 illustrates how these principles apply in a commercial tendering context. The Court held that a tenderer was not bound to proceed with a proposed sub-contract, notwithstanding language referring to a commitment, because expressly “critical” matters were yet to be agreed (including scope, KPIs, milestone penalties and pricing) and remained open for future negotiation, and the overall framing was of a proposal rather than an immediately binding deal.

The Court identified a non-exhaustive list of indicia relevant to whether the parties objectively intended to create legal relations, spanning the terms and form of the putative agreement, the parties’ relationships, and other relevant indicia, including:

• the nature and extent of consensus reached on important matters;
• the clarity and certainty of the terms agreed;
• mutuality of promises between the parties;
• the commercial balance of the arrangement;
• the involvement of legal representatives in the negotiation;
• whether the arrangement was reduced to writing and, if so, signed;
• the language and formality used;
• the parties’ relationship and history of prior dealings;
• what was, and was not, said at the relevant time;
• relevant industry practice; and
• conduct after the alleged agreement was made, including communications to third parties (which may carry more weight than internal communications).

Formal requirements

As a general rule, a contract does not need to be in writing to be enforceable. Verbal contracts, and contracts formed by conduct, are binding in Australia, provided that all the essential elements are present. However, a verbal contract may present practical difficulties with evidence about the specific terms.

Certain categories of contract must be in writing, or evidenced in writing, under statute. This includes contracts for the sale or other disposition of an interest in land, guarantees, consumer credit contracts, and certain financial agreements and consents. Parties should check the specific state or territory legislation that applies to the relevant contract type, since these formal requirements are not uniform across jurisdictions.

Electronic contracts and electronic signatures have the same legal effect as paper documents and handwritten (“wet ink”) signatures for most contract types, under the Electronic Transactions Act 1999 (Cth) and equivalent state and territory legislation, provided the electronic signature identifies the signatory and indicates an intention to be bound. Exceptions apply for particular transaction types, including some of the categories that must be in writing referred to above.

Practical drafting considerations

• Ensure, where possible, that the agreement is in writing. This will assist with meeting the elements of a contract, clarity on the terms, and avoiding disputes down the track. Use a letter of intent, heads of agreement or memorandum of understanding if the negotiations are complex or lengthy. Use precise and concise language and ensure the contract covers all essential commercial terms, and make sure any variations or changes are recorded properly in writing.
• Ensure certainty before treating an agreement as concluded. At a minimum, correctly identify the parties (full legal names, ABN or ACN, and addresses, and the correct contracting entity where a trust, partnership, or corporate group is involved), and clearly define scope, price and payment terms, and timing. An agreement that leaves an essential term open, without a clear process for finalising it, risks a finding that no contract exists for want of certainty.
• Signal intention to be bound clearly during negotiations. Use “subject to contract” or equivalent language only where the parties do not intend to be bound until a formal document is executed. Where the parties do intend to be immediately bound by preliminary correspondence (for example, a term sheet or letter of intent), state this expressly and ensure the document records all essential terms rather than leaving them for later negotiation. Ambiguous language, such as describing a party as committed without more, is unlikely to be treated as an unambiguous acceptance of binding obligations.
• Address teaming and tender arrangements expressly. Where a sub-contract or supply arrangement is contemplated as part of a tender process, state expressly whether a teaming or collaboration arrangement is intended to bind the parties to proceed to a sub-contract if the tender succeeds, and on what terms. Absent an express agreement, courts will not readily infer such a binding obligation, particularly where pricing or scope remains to be settled by reference to the terms of the head contract.
• Use appropriate execution blocks. Execute in accordance with section 127 of the Corporations Act 2001 (Cth) for companies, and confirm appropriate authority for trustees, partners, or other authorised signatories before treating the contract as executed.
• Confirm applicable statutory form requirements at the outset of drafting where a contract must be in writing (for example, land, guarantees, or consumer credit), rather than assuming a signed document will automatically satisfy those requirements.
• Where electronic execution is proposed, check the relevant legislation to confirm whether the transaction is subject to an exception under the Electronic Transactions Act 1999 (Cth) or its state and territory equivalents, and that the method of electronic signature reliably identifies the signatory and their intention to be bound.
• Cover the commercial essentials at drafting stage: description of goods and services and their conformity with specification, price and any variation mechanism, service levels and consequences for failing to meet them, milestones and consequences of delay, warranty scope and duration, and the commencement, duration, and termination (including automatic renewal) of the arrangement.
• Build capacity and authority checks into the contract formation process as standard practice, including verifying a corporate counterparty’s status and the authority of the individual signing on its behalf.
• Keep a record of pre-contractual communications (quotes, invoices, emails) even where the final agreement is reduced to writing. These records may assist in resolving disputes about the timing of formation and the content of terms not expressly recorded, and reduce reliance on inference from conduct.

Common pitfalls

• Treating an invitation to treat as an offer, or vice versa — most commonly with advertisements, price lists, displays of goods, and calls for tenders, none of which are ordinarily offers capable of acceptance.
• Assuming that a reply which changes any term of an offer is an acceptance. Under the mirror image rule, it is a counter-offer, and it extinguishes the original offer.
• Leaving essential terms, such as price or scope, to be agreed later without a clear contractual mechanism for fixing them, and then treating the arrangement as a binding contract in the interim.
• Assuming that expressions of commitment in commercial correspondence, without more, amount to an intention to be immediately bound. As Cirrus illustrates, courts will scrutinise the language used, the extent of consensus on essential terms, and the surrounding commercial context before inferring a binding contract from informal exchanges.
• Relying on a course of dealing or conduct to establish that a contract exists, where the conduct does not clearly demonstrate agreement on all essential terms. The courts have confirmed that contracts will rarely be inferred from conduct alone.
• Overlooking the statutory writing requirements applicable to guarantees, land dealings, and consumer credit contracts, and treating an oral or informal agreement in those categories as enforceable.
• Failing to check a signatory’s authority, particularly for corporate counterparties, resulting in a purported contract that the counterparty is not in fact bound by.
• Confusing a contract that has not yet been assessed for unfair terms with a contract that has not yet been formed. These are distinct questions: a term can only be assessed as unfair once a contract, including its standard form terms, has been validly formed. Refer to Awelle’s separate article on the unfair contract terms regime for that analysis.

This article is prepared for general guidance and comment only, and neither purports nor is intended to be advice on any particular matter.