Implied Agreements Explained: Legal Guide For Australian Businesses

Running a business in Australia moves fast. Work kicks off before paperwork is finalised, you keep supplying a loyal customer after a contract expires, or a deal is agreed on a call and confirmed with a simple “sounds good” email.

But if nothing formal is signed, are you legally bound? In many cases, yes - through what the law calls an “implied agreement”.

This guide breaks down what implied agreements are, when they arise in business, how courts assess them, and practical steps you can take to reduce risk. We’ll also cover how implied terms can be read into your written contracts and what to do if a dispute pops up. By the end, you’ll know the key concepts to protect your position and keep your commercial relationships on track.

What Is An Implied Agreement?

An implied agreement (sometimes called an implied contract) is a legally binding agreement that’s inferred from behaviour, circumstances, or the commercial context - rather than set out in express written or spoken terms.

Two helpful categories:

• Implied-in-fact: Your conduct shows a mutual intention to contract. For example, you keep delivering services each month and your client keeps paying - even though the last written contract expired.
• Implied-in-law (quasi-contract): The law imposes an obligation to prevent unjust enrichment (for example, you conferred a benefit and it would be unfair for the other party not to pay), even where there was no intention to contract.

Implied agreements are about substance over form. If the way you and the other party behave looks like a contract in practice, the law may treat it like one.

It’s also important to distinguish implied agreements from express contracts made informally. A contract formed by clear words in a call, text or email is still an express contract, just not a formal document. The legal test is the same: was there offer and acceptance, consideration, an intention to create legal relations, and certainty?

When Do Implied Agreements Arise In Business?

Implied agreements can emerge in everyday situations such as:

• Continuing after expiry: Work continues after a fixed-term contract ends, with invoices issued and paid as usual.
• Pre-contract work: You start a project before the final document is signed, relying on heads of terms or a handshake.
• Course of dealing: Your long-standing pattern of dealings and industry practice fill the gaps when specifics weren’t discussed this time.
• Informal instructions: Scope and pricing are exchanged in short emails or a purchase order, but no formal agreement follows.
• On-the-spot transactions: Everyday examples include ordering at a café or booking a service - the law implies you’ll pay the going rate.

If a dispute later arises, a court will examine the whole picture: conduct, communications, invoices, custom, commercial sense, and what a reasonable person would infer from the situation.

Quick reminder: an email chain can form an express contract if the essentials are agreed. Whether an email exchange is binding depends on the clarity of terms and context - see more on emails being legally binding. Likewise, verbal agreements can be enforceable if the legal elements are present.

Are Implied Agreements Enforceable Under Australian Law?

Yes - if the usual elements of a contract are established through conduct and context. Courts look for:

• Offer and acceptance: Clear conduct that indicates an offer was made and accepted (for example, a quote sent, work performed, and invoices paid).
• Consideration: Something of value exchanged (payment, goods, services).
• Intention: An objective intention to create a legal relationship (usually presumed in commercial dealings).
• Certainty: Sufficiently clear terms - price, scope, timing or a workable mechanism for determining them.

If these are satisfied, a court may find a binding contract existed even without a signed document. Where the facts don’t support a contract, the law may still grant a remedy in restitution to avoid one party being unjustly enriched.

Where matters often get tricky is which terms apply. You may agree on price and scope by conduct, but disagree later about deadlines, warranties or IP ownership. Uncertainty is the main risk of relying on implied agreements instead of clear written terms.

If a contract was formed but later needs to change, ensure variations are captured properly - poorly documented changes can be disputed. For guidance on changing terms the right way, see amending contracts.

Implied Terms Inside Written Contracts

Even where you do have a written contract, the law can imply additional terms into it. This generally happens through:

• Statute: The Australian Consumer Law (ACL) implies non‑excludable consumer guarantees for goods and services (for example, acceptable quality and due care and skill). If you sell to consumers or certain small businesses, you’ll need to build ACL compliance into your Customer Contract and operational processes.
• Common law implication in fact: Courts may imply a term to give “business efficacy” to the contract or because it’s so obvious it goes without saying. This uses tests such as the well‑known BP Refinery criteria.
• Custom or usage: A well‑established, notorious industry custom may be implied if both parties were aware or ought to have been aware of it.

What about a duty of good faith? Australian courts have recognised good faith obligations in some contexts, but it’s not a universally implied term in every contract. Whether a good faith obligation applies will depend on the wording of your contract and the specific circumstances.

Takeaway: you can’t assume that silence in a contract means freedom from obligations. Some terms (like ACL guarantees) will apply regardless, while others can be implied to make the deal work sensibly. Clear drafting reduces the room for dispute.

How Can You Reduce The Risk Of Implied Agreements?

You can’t stop people from acting informally, but you can put guardrails around how those actions are interpreted. Practical steps include:

1) Use Clear Written Contracts As Your Default

When you set out services, pricing, timing, IP, liability and termination rights clearly, you control the rules from day one. For client work, a tailored Customer Contract or standard terms and conditions reduces ambiguity and provides a single source of truth.

2) Don’t Start Work Until Key Terms Are Agreed

It’s tempting to “get started” to keep momentum, but beginning work before terms are locked in is the number one way implied arrangements arise. If work must begin, exchange a short letter of engagement or email that records price, scope and any key assumptions.

3) Confirm Conversations In Writing

Follow calls or meetings with a clean recap email. If something material changes, send a variation note and seek a clear “yes” back. These simple habits make it easier to prove what was agreed if expectations diverge later.

4) Manage Purchase Orders And Invoices Carefully

Make sure POs and invoices reference your terms (ideally with a link to a current set of terms). Conflicting paperwork can create uncertainty about whose terms apply, so keep your documents consistent.

5) Refresh Longstanding Relationships

Where work has continued for years on an informal basis, schedule a quick review. Update and reissue terms to match current pricing, service levels, data handling and risk allocation.

6) Put The Right Core Documents In Place

Strong, tailored documents reduce the chance that gaps will be “filled” by implication:

• Customer Contract or Service Agreement: Sets scope, deliverables, fees, timelines, IP, confidentiality, liability and termination. This is your first line of defence against uncertainty.
• Website Terms & Conditions: If you sell or interact online, set platform rules, acceptable use, disclaimers and limitations.
• Privacy Policy: Explains how you collect, use and disclose personal information. A Privacy Policy is required if you are an APP entity (for most businesses, this generally means turning over more than $3m, or falling within specific categories like health service providers, credit providers, or traders in personal information). Even where not strictly required, having a clear Privacy Policy builds trust and transparency.
• Employment Contract: If you hire staff, use a compliant Employment Contract and support it with policies (leave, conduct, safety). This prevents disputes about duties, hours and entitlements.
• Supplier Agreement: Lock in quality standards, delivery timeframes, pricing, warranties and risk allocation for your supply chain.
• Non‑Disclosure Agreement (NDA): Protects confidential information during sales, partnership or investor discussions.
• Shareholders Agreement: If there’s more than one founder, a Shareholders Agreement sets decision‑making, share transfers, disputes and exit terms, so the law doesn’t have to imply outcomes later.

Not every business needs every document on day one, but most will need several. Prioritise the agreements that touch your customers, team and suppliers.

7) Build ACL And Consumer Protections Into Your Processes

The Australian Consumer Law sets baseline rules for quality, remedies and fair dealing. Train your team on refunds and warranties, align your terms with your operational policies, and ensure your advertising avoids misleading statements. If you’re unsure how the ACL applies to your offering, consider speaking with a consumer law specialist.

8) Keep Version Control And Records

Store signed agreements, variations, email recaps, POs and invoices together. Good record‑keeping makes it far easier to demonstrate what was agreed - and what wasn’t - if a disagreement arises.

What Happens If There’s A Dispute?

If there’s a disagreement about whether an agreement exists (or what its terms are), courts take a practical, evidence‑based approach. They typically consider:

• Conduct and communications: What was said and done, and how would a reasonable businessperson interpret it?
• Documents: Proposals, POs, emails, text messages, invoices, and any acknowledgement of terms.
• Course of dealing: How you’ve interacted previously and whether a consistent pattern emerges.
• Custom and commercial context: Established industry practices and what makes business sense.
• Statutory overlays: Non‑excludable guarantees and other mandatory rules.

Depending on the facts, a court might find a binding express or implied contract and enforce it (for example, to pay for services rendered), or award restitution to avoid unjust enrichment. In some cases, a contract might fail for uncertainty or other issues - here’s a helpful overview of what can make a contract invalid.

In practice, many disputes are resolved commercially once the evidence is assessed. Early legal guidance helps you evaluate your position and negotiate a practical outcome before costs escalate.

Common Questions We Hear

Is a verbal “go ahead” enough? Potentially. If the key elements of contract formation are present, a verbal agreement can be enforceable - but it’s much harder to prove. Follow up with a short written recap to lock in the basics.

Do emails create implied agreements? Often, emails create an express contract when the essentials are clear and agreed. Whether an email exchange is binding depends on the content and context - more here on email contracts.

Can we exclude implied terms? You cannot exclude non‑excludable statutory guarantees (like core ACL rights). Some other terms may be disclaimed or clarified, but courts won’t imply terms that conflict with the deal’s express wording. Clear drafting is the best tool to avoid unwanted implications.

Key Takeaways

• Implied agreements arise from conduct and context; if you act like there’s a deal, the law may treat it as binding.
• The main risk isn’t whether a contract exists, but which terms apply - clarity and documentation reduce disputes.
• Statutory rules (like the ACL) and carefully limited common law tests can imply terms into your written contracts.
• Use written agreements as your default, confirm conversations in writing, and avoid starting work until key terms are agreed.
• Put core documents in place - a tailored Customer Contract, Website Terms, appropriate Privacy Policy (where required), Employment Contracts, supplier terms, NDAs and a Shareholders Agreement if you have co‑founders.
• If a dispute arises, the outcome will turn on evidence of conduct, documents and commercial context - get early advice to protect your position.

If you’d like a consultation about managing implied agreements and putting the right contracts in place for your business, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no‑obligations chat.