NZS 3910 §13 dispute resolution — mediation, adjudication and the Construction Contracts Act sequence (NZ 2026)

sp8002
May 30
7 min read

§13 of NZS 3910:2023 sets the dispute sequence — internal review, mediation, then adjudication or arbitration. The Construction Contracts Act 2002 runs parallel, giving either party a statutory adjudication right. Reading them together matters. A $40k variation dispute can settle in three weeks or run for nine months.

By Steve Parker · Trueworks · NZ construction estimation · 7 min

§13 is the contractual dispute pathway. The Construction Contracts Act 2002 is the statutory pathway. The two run in parallel and the contractor often has the right to choose. The first 20 working days after a dispute crystallises decide whether it closes in mediation or escalates to adjudication.

By Steve Parker · Trueworks · NZ construction estimation · 7 min

What you'll learn in this post

What §13 of NZS 3910:2023 actually requires
How the Construction Contracts Act 2002 runs alongside §13
The 5-item check before triggering or responding to a dispute notice

Quick answer: §13 of NZS 3910:2023 is the contractual dispute-resolution clause. It sets a sequence: notification, internal review by the Engineer's determination process, then mediation, then arbitration or adjudication if mediation fails. The Construction Contracts Act 2002 §25 grants either party a statutory right to refer a dispute to adjudication at any time, with an adjudicator's determination binding on an interim basis. Reading §13 and the Act together is the only defensible position. A $40k disputed variation can resolve in mediation in 2-4 weeks; if it escalates to adjudication, expect 6-10 weeks plus legal cost.

§13 of NZS 3910:2023 governs dispute resolution. The Construction Contracts Act 2002 governs statutory adjudication. The two regimes overlap, and most disputes on NZ residential head contracts move through one, the other, or both. Reading them in sequence is how the disputes that should close at mediation close at mediation, and the ones that won't get to a binding determination on a defensible timeline.

This post is the working-CA / working-contractor read of §13 — the contractual sequence, the parallel statutory pathway, and the 5-item check before triggering the clause.

What §13 of NZS 3910:2023 actually says

§13.1 — internal determination

The first step is the Engineer's determination under whichever substantive clause the dispute arose from — §14 for a variation valuation, §10.3 for an EOT, §12.3 for a payment schedule. The Engineer's determination is the starting point. Either party may dispute the determination.

§13.2 — notice of dispute

A party that disputes the Engineer's determination serves a written notice of dispute on the other party and the Engineer. The notice:

Identifies the determination disputed
States the grounds
States the relief sought
Triggers the dispute-resolution sequence

§13.3 — mediation

§13.3 requires the parties to attempt mediation in good faith before escalating. The mediator is appointed by agreement (or, failing agreement, by the body named in the contract particulars — typically NZIAC, AMINZ, or NZDRC). Mediation timeframe is typically set by the parties and the mediator — most residential disputes set 1-4 weeks from appointment.

§13.4 — arbitration or adjudication

If mediation fails, §13 escalates to:

Arbitration under the Arbitration Act 1996 (the contractual default)
Adjudication under the Construction Contracts Act 2002 (the statutory parallel)

§13.4 typically directs to arbitration; the Construction Contracts Act 2002 provides the parallel statutory adjudication right that cannot be contracted out of.

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How the Construction Contracts Act 2002 changes the picture

The Construction Contracts Act 2002 (CCA) sits behind every NZ construction contract and overrides any clause that conflicts with it. The two CCA points that matter for §13 disputes:

§25 of the CCA — right to adjudicate

Either party can refer any dispute to adjudication at any time, regardless of whether mediation has been attempted under §13.3. The adjudicator must be appointed within 5 working days, and the determination is typically issued within 20 working days of submission. The determination is binding pending any final arbitration or court determination.

§59 of the CCA — enforceability

An adjudicator's determination is enforceable as a debt in the District or High Court without re-litigation of the merits. This is the most powerful procedural tool in NZ residential construction — a contractor with an unpaid §12.3 determination can typically convert it to a court-enforceable debt in 4-8 weeks.

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How §13 fails on NZ residential builds

1. The "we'll talk about it next week" failure. A variation valuation dispute arises in month 6. Both sides talk on site, exchange emails, neither serves a §13.2 notice. Three months later, the issue compounds with a payment-schedule dispute and an EOT claim. By the time §13.2 is finally served, the dispute is a $90k issue rather than the $25k it started as. Resolution costs scale with complexity.

2. The mediator-skipping failure. The contractor or principal jumps directly to adjudication under the CCA, skipping §13.3 mediation. This is procedurally permitted under the CCA, but on residential work, the mediation step is where 60-70% of disputes settle. Skipping it puts the parties into a 6-10 week adjudication process and $15-40k of legal cost that mediation would have avoided.

3. The "binding vs interim" confusion. An adjudicator's determination under the CCA is binding on an interim basis — it can be revisited in arbitration. Parties sometimes treat the adjudicator's determination as final and don't preserve their position for arbitration. Six months later, they discover their right to arbitrate has lapsed under the contract particulars.

The reference table

| Step | Clause / Act | Default timeframe | Cost band (typical residential dispute) | |---|---|---|---| | Engineer's determination | §13.1 / substantive clause | Per contract | Zero direct cost | | §13.2 notice of dispute | §13.2 | Triggered on dispute | Zero direct cost | | Mediation | §13.3 | 2-6 weeks | $3-10k mediator fee, split | | Adjudication under CCA §25 | CCA §25 | 20 working days from submission | $8-25k adjudicator fee plus legal | | Arbitration | §13.4 / Arbitration Act 1996 | 4-12 months | $40-150k+ legal and arbitrator | | Court (debt enforcement only) | CCA §59 | 4-8 weeks | $5-15k legal |

Worked example

A $1.6M residential head contract under NZS 3910:2023. The Engineer determines a §14.4 variation valuation at $32k. The contractor disputes — the contractor's claim was $58k, built up on first-principles cost.

The mediation-path version: the contractor serves a §13.2 notice within 10 working days. Both parties agree to mediation under §13.3. Mediator appointed within 14 days. Mediation takes one day. Parties settle at $47k. Total cost: $4.5k each in mediator and legal. Total time from §13.2 notice to settlement: 5 weeks.

The adjudication-path version: the contractor serves an adjudication notice under CCA §25, skipping §13.3 mediation. Adjudicator appointed within 5 working days. Submissions exchanged over 20 working days. Determination issued at $51k. Total cost: $14k each in adjudicator fees and legal submissions. Total time: 7 weeks. Plus the relationship is now adversarial through to Practical Completion.

The drift-and-compound version: neither party serves §13.2; the dispute drifts. Three months later, additional variations are disputed and stacked. Five months later, an EOT claim is unresolved. Eventually one party serves adjudication under CCA §25 on the bundled package. Adjudication runs 12 weeks. Total cost: $35k+ each. Plus the project is at Practical Completion with retentions and final account disputes still live.

What to check before triggering or responding to a §13 dispute

Five items, every time:

The Engineer's determination is in writing with reasoning — §13 disputes turn on the determination being challenged
The §13.2 notice names the determination, the grounds, and the relief sought — a vague notice is a procedurally weak position
Mediation under §13.3 is genuinely attempted — adjudication is the right pathway when mediation has failed, not when it's been skipped
The Construction Contracts Act 2002 timing is tracked — adjudication submissions are tight, and missing the response window is fatal
The right to arbitrate is preserved if the matter is escalated to CCA adjudication and may need to be reopened

If those five items are present, the dispute moves through the process defensibly. If they're not, the procedural defects open the door for the adjudicator or arbitrator to penalise either party.

FAQ — NZS 3910 §13 and CCA dispute resolution

Q1: Can the contractor go straight to CCA adjudication without serving §13.2? Yes. The Construction Contracts Act 2002 §25 grants a statutory right to adjudicate any dispute at any time, regardless of contractual prerequisites. §13.3 mediation is a contractual obligation but cannot fetter the statutory right.

Q2: Is the adjudicator's determination final? No — it's binding on an interim basis. Either party may refer the substantive dispute to arbitration or court for a final determination. In practice, most adjudicator determinations stand because the cost of arbitration is high.

Q3: What's the cost difference between mediation and adjudication? On a typical $40-80k residential dispute: mediation runs $3-10k mediator fee plus minimal legal — total $5-15k. Adjudication runs $8-25k adjudicator fee plus 30-60 hours of legal — total $15-40k. The cost ratio is roughly 1:3 in favour of mediation.

Q4: Can the Engineer mediate the dispute? No. The Engineer's role under §6.1 is impartial determination — they're not a mediator. Once a determination is disputed under §13.2, the Engineer's role on that point is largely exhausted (subject to revisiting determinations under §6 if new information emerges).

Q5: Does §13 cover disputes that arise after Practical Completion? Yes. §13 applies to all disputes arising under the contract, including final-account, defects, retentions release, and Defects Liability Period disputes under §10. The Construction Contracts Act 2002 also continues to apply post-PC for unpaid amounts.

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