Most business owners assume that if something’s “in writing and signed”, it’s automatically legally binding.
In reality, some contracts can be unenforceable in New Zealand - which means that even if you’ve got a document (or a set of emails) that looks like a deal, you might not be able to rely on it if things go wrong.
This 2026 update reflects how contracts are commonly formed and managed today (especially online), and why getting your legal foundations right from day one is still one of the easiest ways to avoid expensive disputes later.
Let’s break down what “unenforceable” means, when it can happen, and what you can do to protect your business.
What Does “Unenforceable Contract” Mean In New Zealand?
A contract is generally unenforceable when:
- there is an agreement (or something that looks like one), but
- the law won’t let one party use the courts to make the other party comply with it (or claim damages for breach).
This is a bit different from a contract that is:
- void (treated as if it never existed), or
- voidable (valid unless and until one party cancels it), or
- illegal (involving unlawful activity, where the courts typically won’t assist either party).
In plain terms: an unenforceable contract might look fine on the surface, but if a dispute happens, you may find you can’t actually “enforce” your rights the way you expected.
For small businesses, this usually comes up when you’re relying on handshake deals, short-form templates, rushed “quick agreements” over email, or terms that haven’t been properly tailored to how you actually operate.
What Makes A Contract Legally Binding (So It Can Be Enforced)?
Before we talk about when a contract becomes unenforceable, it helps to know what a contract typically needs in the first place.
While contract law can get technical, most enforceable contracts in New Zealand require:
- Offer (one party proposes clear terms)
- Acceptance (the other party agrees to those terms)
- Consideration (something of value is exchanged, like money for services)
- Intention to create legal relations (usually assumed in business settings)
- Certainty (the key terms are clear enough to be workable)
- Capacity (the parties are legally able to contract)
If you’re negotiating and signing regularly, it’s worth having a consistent contracting approach - whether that’s a tailored Service Agreement, strong terms and conditions, or a master agreement with project scopes attached.
This is also where issues begin: if one of those basics isn’t there, or the law imposes extra requirements (like needing certain contracts in writing), your “contract” may be difficult or impossible to enforce.
Common Reasons A Contract Can Be Unenforceable
There isn’t one single reason a contract becomes unenforceable - it’s usually about how the agreement was formed, what it contains, or whether the law allows it to be enforced.
Here are some of the most common unenforceability issues we see for New Zealand businesses.
1) The Contract Is Too Uncertain Or Incomplete
If key terms are missing or unclear, a court may decide there isn’t a sufficiently certain agreement to enforce.
This can happen when parties agree on the “big picture” but leave out (or never finalise) core details, like:
- the exact scope of work (what is included and excluded)
- pricing, payment timing, or what triggers extra charges
- timeframes and deadlines
- service levels or quality standards
- how changes will be handled (variations)
- what happens if something goes wrong (termination rights, refunds, liability limits)
It’s common in fast-moving projects - a client says “yes”, you start work, and the written terms follow later (or never).
A practical fix is to use a clear base contract and attach project specifics as you go. For many service businesses, a well-drafted Master Services Agreement with a statement of work process keeps things flexible without sacrificing enforceability.
2) The Agreement Wasn’t Properly Accepted (Or Acceptance Was Conditional)
Sometimes a “deal” is more like an ongoing negotiation.
For example, you might send terms, the other party replies with “Looks good - subject to finance” or “We’ll sign once our director approves” or “We accept if you can deliver by Friday”. That may not be acceptance at all - it may be a counteroffer, or acceptance subject to conditions.
In contract law, when acceptance is conditional, you might not have a binding agreement until the condition is satisfied.
This issue also shows up in online contracting when:
- terms are linked but not clearly incorporated
- there’s no clear “click to accept” step
- different versions of terms are circulating
If you run an online business, your Website Terms and Conditions should make acceptance and incorporation crystal clear (so you’re not arguing later about whether the customer agreed to anything at all).
3) One Party Didn’t Have Legal Capacity (For Example, A Minor)
Capacity is a legal way of saying someone is allowed to enter into a contract and be held to it.
In business, capacity problems can arise when a contract is entered into by:
- a person under 18
- someone who lacks the mental capacity to understand the agreement
- someone who didn’t have authority to sign on behalf of a company or organisation
Contracts with minors aren’t automatically invalid in every situation, but there are specific rules and protections that can affect enforceability.
If your business deals with younger customers (or you’re hiring a young worker), it’s worth understanding the risks early - including whether you need capacity checks or different contracting processes.
4) The Contract Was Signed Under Duress, Undue Influence, Or Unconscionable Pressure
Even if the wording is clear, a contract may be unenforceable (or cancelled) if the law considers the agreement wasn’t genuinely voluntary.
Common examples include:
- pressure to sign “right now” with a serious threat (like terminating a supply arrangement immediately)
- one party taking advantage of a power imbalance (particularly where the other party is vulnerable)
- terms that are so one-sided that they look exploitative in the circumstances
This is one reason it’s risky to force “sign today or else” deals, especially with consumers or small suppliers.
It’s also why, when you’re the party being pressured, it’s smart to pause and get advice before signing - even if it feels awkward in the moment.
5) Misrepresentation Or Misleading Conduct
If one party is induced to enter a contract because of a false statement of fact, the contract may be cancellable and certain terms may be unenforceable.
Misrepresentation can be:
- innocent (genuinely mistaken)
- negligent (careless)
- fraudulent (dishonest)
From a business perspective, this often overlaps with compliance under the Fair Trading Act 1986 (which prohibits misleading or deceptive conduct in trade) - especially in advertising, sales pitches, and negotiations.
Common risk areas include:
- overstating performance or results (“this will double your revenue”)
- incorrect claims about what’s included (“support is included” when it’s not)
- statements about future events presented as guaranteed outcomes
- omitting important information that makes the overall impression misleading
Keeping your sales process aligned with your written contract helps a lot here - and if you have a more complex arrangement (like a vendor finance or staged purchase), it’s worth properly documenting what has been represented and what hasn’t.
6) The Contract Is Illegal Or Contrary To Public Policy
If a contract involves unlawful activity, it may be unenforceable (and in some cases, void). Even if only part of the contract is illegal, it can still cause major enforceability issues.
For example, agreements involving under-the-table cash payments can expose both parties to legal and tax risk, and can make it much harder to enforce payment or performance obligations later. If this is a concern in your industry, it’s worth understanding the risks of cash-in-hand arrangements from the outset.
“Public policy” is a broader category where the courts may refuse to enforce certain arrangements even if they aren’t strictly illegal, because enforcing them would undermine the integrity of the legal system or harm the public interest.
7) The Contract Contains Unfair Or Unenforceable Terms
Sometimes the contract exists and is generally valid - but certain clauses within it can’t be enforced.
This can happen where terms are:
- too vague to apply in practice
- penalties (designed to punish rather than compensate)
- unfair in a way that breaches consumer or unfair contract term rules (depending on the context)
- inconsistent with mandatory legal rights
Two common examples for small businesses are:
- Liability clauses that try to exclude liability in situations where the law won’t allow it (particularly for consumers).
- Restraint clauses (like non-competes) that are broader than necessary, which can make them difficult to enforce.
If you rely on restraints to protect your business (for example, preventing a contractor or senior employee from immediately competing), the wording needs to be carefully tailored. A generic Non-Compete Agreement approach often isn’t enough - because enforceability depends heavily on what’s reasonable in your specific circumstances.
Do Contracts Need To Be In Writing To Be Enforceable?
In New Zealand, many contracts can be enforceable even if they’re verbal.
But “can be enforceable” and “easy to enforce” are very different things.
Even where the law doesn’t strictly require writing, having a written contract usually makes it far easier to prove:
- what was agreed
- when it was agreed
- who agreed to it (and with what authority)
- what happens if there’s a dispute
For some types of arrangements, there may be legal requirements around writing, signing, or form (for example, certain property-related transactions). And even where there isn’t a strict legal requirement, your industry or the practical risk profile might make a written agreement essential.
If you’re onboarding staff, for example, a clear Employment Contract helps define duties, pay, IP ownership, confidentiality, notice, and termination processes - and it reduces the risk of misunderstandings turning into disputes.
As a rule of thumb: if it’s important enough to argue about later, it’s important enough to document properly now.
How Can You Reduce The Risk Of An Unenforceable Contract?
The good news is that most unenforceability problems are preventable with a bit of structure and the right legal documents.
Here are practical steps you can take to protect your business.
Use The Right Contract For The Right Relationship
A contract should match what you’re actually doing.
For example:
- If you provide services to clients, use a service agreement (not a one-page invoice with a few lines of “terms”).
- If you’re bringing on a contractor, use a contractor agreement with clear IP, confidentiality and scope terms.
- If you’re selling online, ensure your website terms align with your checkout and customer journey.
Using the wrong document (or mixing documents from different industries) often creates gaps, inconsistencies, or clauses that don’t apply - which is exactly where enforceability issues start.
Make The Key Terms Clear (And Put Them Front And Centre)
If you want a contract to be enforceable, the core terms shouldn’t be buried, implied, or left to “common sense”.
Make sure the document clearly covers:
- Deliverables: what you will provide, and what you won’t
- Payment: amount, due dates, invoicing, late fees (if any)
- Timing: milestones, turnaround times, dependencies
- Changes: how variations are approved and priced
- Liability: reasonable risk allocation, not blanket exclusions
- Termination: notice periods, immediate termination triggers, exit obligations
If you’re using online terms, make sure they’re accessible before purchase, and that your customer clearly accepts them (for example, via a tick box or obvious “by purchasing you agree” flow).
Check Authority (Especially In B2B Deals)
A surprisingly common issue in business-to-business contracts is that the person “signing” isn’t authorised to bind the company.
This can happen where:
- a junior staff member signs without approval
- a business partner signs outside agreed internal limits
- someone signs on behalf of an entity that doesn’t actually exist (wrong legal name)
Simple checks help, like confirming the correct legal entity name, the signatory’s role, and whether board or director approval is required for higher-value deals.
Keep A Clean Paper Trail (Emails, Versions, Signatures)
If a dispute arises, you want to be able to show a clear history of:
- the final agreed version of the contract
- any variations
- what was promised during negotiations
- when each version was accepted and by whom
This is especially important for contracts formed over email or messaging platforms. If different versions are floating around, you can end up arguing about what terms were actually agreed - and that uncertainty can lead to enforceability problems.
Don’t Rely On Templates For High-Risk Deals
Templates can be a starting point, but they’re rarely drafted with your specific risks, industry, or business model in mind.
Imagine this: your business takes off, you start working with larger clients, and a dispute hits right when cashflow matters most. If your contract doesn’t properly cover payment protections, scope, or liability, you can end up spending far more fixing the problem than you would have spent getting the contract right initially.
Getting a contract drafted or reviewed early is one of those “set-and-forget” legal steps that can support growth with far less stress.
Key Takeaways
- A contract can be unenforceable when the law won’t allow a party to rely on it in court, even if it looks like a real agreement.
- Common reasons for unenforceability include uncertainty in key terms, lack of proper acceptance, capacity issues, duress or undue influence, misrepresentation, illegality, and clauses that the law won’t uphold.
- Many contracts don’t need to be in writing to exist, but written agreements are usually far easier to prove and enforce if there’s a dispute.
- You can reduce risk by using the right agreement for the relationship, clearly documenting scope and payment terms, confirming authority to sign, and keeping a clean record of versions and variations.
- If your contract is a core part of how you get paid or manage risk, it’s worth getting it drafted or reviewed so it actually protects you when it matters.
If you’d like help reviewing or drafting a contract so you’re protected from day one, you can reach us at 0800 002 184 or team@sprintlaw.co.nz for a free, no-obligations chat.
