Dividing Fences in the ACT: Notice, ACAT and the 50% Cap

In the Australian Capital Territory, a dividing fence dispute is decided by ACAT under the Common Boundaries Act 1981. An applicant must wait 30 days after asking a neighbour to discuss the fence, and any ACAT-ordered contribution is generally capped at half the cost of a basic fence.

Information last verified on 21 July 2026 against the primary legislation. This page presents general legal information, not legal advice.

Jurisdiction scope: This page covers dividing fences law in the Australian Capital Territory only, under the Common Boundaries Act 1981 (ACT), verified 21 July 2026. It does not cover other Australian states or territories, each of which has its own Act; see the linked comparison page for those.

Governing law and ACAT

Dividing fences disputes in the ACT are governed by the Common Boundaries Act 1981 (ACT) and decided by the ACT Civil and Administrative Tribunal (ACAT). Section 4 sets out when an occupier can apply to ACAT for what the Act calls a "new fence determination": the adjoining parcels must not currently be separated by a fence, one occupier must have asked the other to join in erecting one, and either the other occupier has refused or the two cannot agree on a matter relating to construction.

The 30-day wait and the 14-day deemed refusal

Section 4(3) requires an occupier to first give the neighbouring occupier a notice asking them to discuss erecting, and paying for, a boundary fence, and to then wait at least 30 days from that notice before applying to ACAT. Separately, section 4(4) provides that an occupier who does not join in erecting a fence within 14 days of being asked is "taken to have refused to join in erecting the fence." This deemed-refusal rule means a neighbour who simply does not respond within 14 days is treated the same as one who actively refuses, letting the process move to ACAT without requiring an explicit rejection.

ACAT’s powers and the 50% cap

Once ACAT holds a hearing on an application, section 10(2) lets it determine the nature of the fence, the line on which it should be built, which party is responsible for erecting it, the amount to be contributed, and how and when that amount should be paid. Section 10(3) then places a specific limit on that power: if a party asks ACAT to determine that a "basic fence" should be erected, ACAT must not require that party to contribute more than half the cost of erecting a basic fence between the parcels. Section 10(4) removes this cap only where ACAT is satisfied a basic fence is not practicable, or where special circumstances require a fence other than a basic fence.

Why the cap matters

The 50% cap on a basic fence is a meaningful protection: it means a party cannot generally be forced by ACAT to pay more than half the cost of the simplest fence that would do the job, even if the other party wants, and has asked for, something more elaborate. A party who wants a more expensive fence than a basic one is generally expected to bear the additional cost themselves, in line with how New South Wales, Victoria and Queensland each treat a request for a higher-standard fence.

Repairing an existing fence is a separate application

The process described above, sections 4 and 10, is specifically a "new fence determination" for parcels not currently separated by a fence. Where a fence already exists but needs repair or replacement, section 5 provides a parallel but distinct pathway: an occupier who has asked their neighbour to join in repairing or replacing the fence, and been refused or been unable to reach agreement, can apply to ACAT for a "repair determination" instead. A related application, a "repair cost determination" under section 6, deals specifically with disputes over how much repair work should cost, separately from whether the repair itself should happen. Keeping these as distinct application types means an ACT occupier needs to identify which situation, a missing fence or a damaged one, they are actually in before applying.

Why a "basic fence" concept exists

The ACT's basic-fence cap addresses a genuine fairness problem that other states handle differently. Without it, an occupier who simply wants a low-cost, adequate boundary fence could be drawn into paying half the cost of an elaborate fence their neighbour wants, purely because the neighbour applied to ACAT first. By anchoring the default cap to the cost of a basic fence rather than to whatever fence is actually proposed, section 10(3) protects a cost-conscious occupier while still letting ACAT order a more expensive shared fence where a basic one genuinely will not work, under the section 10(4) exceptions for impracticability or special circumstances.

How the ACT compares

The ACT’s ACAT-based process and its 50% basic-fence cap put it in the tribunal group alongside New South Wales, Queensland and the Northern Territory, though the specific cap mechanism is unique to the ACT among these. See dividing fences in Australia for the full comparison, and dividing fences in the Northern Territory for another tribunal-based jurisdiction.

This page is general legal information about neighbour disputes in Australia, verified on 21 July 2026. It is not legal advice, and it does not cover every situation. For advice about your own dispute, consult a legal practitioner admitted in the relevant Australian state or territory.