Extension of Time NZS 3910

What Triggers an Extension of Time Under NZS 3910

Extension of time claims under NZS 3910 are triggered by delays that aren't the contractor's responsibility. The standard recognises several categories of delays that justify extensions.

Clause 13.2 lists the principal's acts that entitle the contractor to an extension of time. These include late provision of access to the site, failure to provide necessary approvals, and variations that affect the programme.

Weather delays are covered under Clause 13.3, but only when they're "exceptionally inclement weather" beyond what would reasonably be expected for the location and time of year. This isn't just any rain delay. It needs to be genuinely exceptional.

Force majeure events under Clause 13.4 include events like earthquakes, wars, or government actions that prevent completion. The 2023 version clarified that pandemic-related restrictions can fall into this category, though each case depends on specific circumstances.

The Extension of Time Process and Notice Requirements

The extension of time process under NZS 3910 has strict notice requirements. Clause 13.1 requires the contractor to give notice of any delay "as soon as reasonably practicable" after becoming aware of the delay.

This initial notice doesn't need to be detailed, but it must identify the event causing the delay and the likely effect on completion. The key word is "practicable", not just "possible". You need to give notice when a reasonable contractor in your position would have identified the delay risk.

Within 10 working days of giving notice (or longer if the contract administrator agrees), you must provide a detailed claim. This claim must include:

• The cause of delay and why it wasn't your responsibility
• The effect on the programme and completion date
• The steps taken to mitigate the delay
• Supporting documentation and records

The contract administrator then has 15 working days to make a determination. If they don't respond within this timeframe, Clause 13.1(d) deems the extension granted as claimed.

Timeframe	Action Required	Responsible Party
As soon as reasonably practicable	Initial notice of delay	Contractor
Within 10 working days	Detailed extension claim	Contractor
Within 15 working days	Determination on claim	Contract Administrator
If no determination	Extension deemed granted	Automatic

Documentation Requirements for Extension of Time Claims

Successful extension of time claims under NZS 3910 require comprehensive documentation. The standard doesn't specify exact requirements, but best practice includes contemporaneous records that clearly show cause and effect.

Your programme should be updated regularly and show the critical path. When delays occur, you need to demonstrate how they affect this critical path and push out completion. A programme that's six months out of date won't support your extension claim.

Daily reports, photographs, and correspondence are crucial. They need to be recorded at the time, not reconstructed months later when you're preparing the claim. Site diaries should record weather conditions, labour availability, and any events affecting progress.

Weather delays require meteorological data from official sources like NIWA. Your site records should correlate with official weather data to support claims for exceptionally inclement weather. Simply saying "it rained a lot" won't cut it.

For variations causing delay, you need the variation instruction, your assessment of delay impact, and evidence that you couldn't mitigate the delay by re-sequencing work.

Common Mistakes in Extension of Time Applications

The most common mistake with extension of time claims under NZS 3910 is late notification. Many contractors wait until they're certain about the delay impact before giving notice, but the standard requires notification as soon as reasonably practicable.

Another frequent error is failing to demonstrate how delays affect the critical path. Just because work is delayed doesn't automatically entitle you to an extension of time. The delay must actually push out completion or a key milestone.

Contractors often submit poorly documented claims that don't clearly link cause and effect. The contract administrator needs to understand what happened, why it wasn't your fault, and how it affected completion. Vague claims get rejected.

Concurrent delays cause particular problems. When both principal and contractor causes contribute to delay, the contractor may only get partial extension. You need to clearly separate delays and show which elements weren't your responsibility.

Some contractors try to claim extension for delays they could have mitigated through better planning or resource allocation. The standard expects reasonable mitigation measures, and failure to take them can reduce your entitlement.

The Contract Administrator's Assessment Process

When assessing extension of time claims under NZS 3910, the contract administrator must act fairly and reasonably. They're not the principal's representative in this process. They have a quasi-judicial role requiring impartial assessment.

The contract administrator should examine whether the delay event falls within Clause 13 categories and whether proper notice was given. They'll assess the programme impact and whether reasonable mitigation measures were taken.

For weather-related claims, they'll typically check official meteorological data against historical averages for the area. What constitutes "exceptionally inclement weather" varies by location and season.

The assessment should consider the project's critical path at the time of delay, not retrospectively. This is why keeping programmes current is essential. The contract administrator needs to understand what was critical when the delay occurred.

If the contract administrator rejects a claim or grants less extension than requested, they should explain their reasoning. This explanation is important for any subsequent dispute resolution.

Where multiple causes of delay overlap, the law on concurrent delay matters. The dominant English approach is the Malmaison principle, set out in Henry Boot Construction (UK) Ltd v Malmaison Hotel (Manchester) Ltd [1999] 70 ConLR 32 (Technology and Construction Court) and applied in Multiplex Constructions (UK) Ltd v Honeywell Control Systems Ltd [2007] EWHC 447 (TCC). Under Malmaison, where a contractor-cause delay and an excusable employer-cause delay run concurrently, the contractor is entitled to the extension of time (which protects against liquidated damages) but is not entitled to additional cost for the period of concurrent delay. The principle is widely cited in NZ practice; the NZ Supreme Court has not yet definitively adopted or modified it, so its application in any specific NZ dispute should be confirmed against current case law.

Managing Extension of Time Deadlines Across Multiple Claims

Large projects often have multiple extension of time claims running simultaneously. Each claim under NZS 3910 has its own notice periods and deadlines, creating a complex web of requirements to track.

The challenge multiplies when delays are interconnected. A variation might cause delay, which then affects your ability to mitigate weather delays, which pushes other work into winter conditions. Each element may require separate notice and claims.

Keeping track of all these deadlines manually is practically impossible on complex projects. You need systematic tracking of notice periods, claim submission deadlines, and contract administrator response timeframes.

The 10 working day deadline for detailed claims can be extended by agreement with the contract administrator, but you need to request this before the deadline expires. Don't assume they'll grant extensions retrospectively.

When multiple delay events affect the same completion milestone, the cumulative effect determines the total extension. However, you still need to demonstrate each individual delay event and its contribution to the overall impact.

Recovery Strategies When Extension Deadlines Are Missed

Missing extension of time deadlines under NZS 3910 doesn't necessarily end your entitlement, but it makes recovery much harder. The first step is understanding why the deadline was missed and whether any exceptions apply.

If you can demonstrate that the delay event wasn't reasonably discoverable until after it would normally trigger notice requirements, you may still have grounds for an extension. This often applies to latent defects or gradually developing problems.

Some contract administrators will accept late claims where the delay is ongoing and future impact can still be assessed. While not guaranteed, it's worth submitting the claim with explanation for the late submission.

For major delay events, consider whether they might qualify under force majeure provisions, which sometimes have different notice requirements. The key is acting as soon as you recognise the problem, even if initial notice periods have passed.

Document your attempts to comply with the procedures and why normal deadlines weren't achievable. This creates a record for potential dispute resolution if the contract administrator rejects late claims.