Tree Regulations

How the rules apply

The regulations use several zones around power lines. These zones help determine when trees must be trimmed, when notices can be issued and what restrictions apply.

The regulations include three zones around a power line. These help explain when vegetation is getting too close and when it needs to be cut back.

• Growth Limit Zone: The space immediately around a power line that must be kept clear of vegetation. The size and shape of the growth limit zone depends on the voltage of the line and in some cases, the span length of the line.
• Cut-Back Zone: The cut back zone is the distance measured 1 metre beyond the growth limit zone. If a tree is growing into the growth limit zone, it needs to be trimmed back far enough to reach the cut-back zone unless a dispensation applies.
• Hazard Warning Notice Zone: The hazard warning notice zone is the distance measured 2 metres beyond the growth limit zone If vegetation enters this zone, Westpower may issue a hazard warning notice to alert the tree owner.

If a tree qualifies for its first cut or trim under the regulations, Westpower will pay for that work. After that, keeping the tree clear of the power line — and paying for any trimming that’s needed — is the tree owner’s responsibility.

Different rules can apply in some circumstances, so check with Westpower if you are unsure.

Diagram showing the growth limit zone around an overhead power line. Trees and other vegetation must be kept outside the required clearance area around the conductors.

Trees that could fall into a power line

The treefall hazard zone is an area that extends 24 metres from the growth limit zone.

Trees within this zone may be assessed by a lines company. This does not mean every tree in the zone is a hazard. It means the tree may be assessed if there is concern that, because of its condition, size or location, it could fall onto the power line. A formal treefall hazard notice can only be issued if the tree is assessed as a moderate or high hazard.

Diagram showing the treefall hazard zone around an overhead power line, extending 24 metres beyond the growth limit zone. Trees within this area may be assessed for the risk of falling onto the line, including factors such as tree height and defects.

Planting a new tree near a power line

The low height planting zone extends 24 metres horizontally from the power line. The low height planting zone means you must not plant a tree if you reasonably expect it could grow taller than its distance from the power line.

If you plant a tree in breach of this rule:

• you may be liable for damages
• you may be responsible for the cost if the tree later needs to be cut, trimmed or removed
• you cannot use a ‘no-interest’ tree notice to transfer responsibility for managing the tree to the lines company

The planting restriction does not apply to trees that grow naturally. However, if a self-sown tree within the low height planting zone later needs to be cut, trimmed or removed, the tree owner may be responsible for the cost.

There are some exceptions. The low height planting zone does not apply:

• on existing forest land
• in urban areas
• to shelterbelts
• on land administered under the Conservation Act 1987.

Not sure whether your property is in an urban area? Check your district plan or contact your local council.

Diagram showing the low height planting zone extending 24 metres horizontally from the conductors on each side of an overhead power line. Within this area, the permitted height of newly planted trees reduces as they are planted closer to the line.

Vegetation growing above the line – ‘clear to the sky’

For some power lines, the growth limit zone extends vertically above the line as well as around it. This is known as ‘clear to the sky’ and means vegetation must also be kept clear above the line.

Clear to the sky applies to higher-voltage lines in both urban and non-urban areas and to lines at 11 kV or below outside urban areas.

Diagram showing the growth limit zone around an overhead power line, with the clearance extending vertically upwards to the sky.

What happens if a tree grows too close to a line?

If a tree is too close to a power line, Westpower may contact the tree owner. Depending on the situation, this may include:

• providing information or advice
• issuing a hazard warning notice
• requiring the tree to be cut back
• taking further action allowed under the regulations if the issue is not addressed

The exact process depends on the type of risk and which rules apply. If you receive a notice, it's important to read it carefully and act within the required timeframe.

Tree notices and what they mean

What if I disagree with a notice or assessment?

Different review or dispute options may be available depending on the type of notice or issue.

For some matters under the regulations, disputes may be referred to the Tree Arbitrator. The WorkSafe website lists the current Tree Arbitrator and further information. Some issues may also be raised with Utilities Disputes, depending on the complaint.

If you disagree with the notice you receive, contact Westpower as soon as possible so the next steps can be explained.

Offences and penalties

Tree owners can be fined if they do not meet certain requirements under the regulations.

Cut trim notices

A tree owner might commit an offence if, without reasonable excuse, they:

• do not have a tree cut or trimmed as required by a cut trim notice
• do not tell Westpower the time and location of the work at least three working days before it takes place.

If convicted, the tree owner may be fined up to $10,000. If the offence continues, a further fine of up to $500 for every day or a part day may apply.

Treefall hazard notices — from 23 July 2028

From 23 July 2028, a tree owner may commit an offence if, without reasonable excuse, they:

• do not have a tree removed within the timeframe required by a treefall hazard notice
• do not tell Westpower the time and location of the removal as required.

If convicted, the tree owner may be fined up to $10,000.

Low height planting zone

Not complying with the low height planting zone restrictions is not itself an offence. However, it may affect who is responsible for the cost of future tree trimming or removal and the options available to the tree owner under the regulations.

Can I trim or remove the tree myself?

If you, the tree, or any tools or equipment could come within 4 metres of a power line, do not attempt the work yourself. Contact Westpower first.

Cutting or removing trees near live power lines is dangerous. It can lead to serious injury, electric shock, fire, power outages and damage to property or electricity infrastructure. Trees or branches can fall or swing unexpectedly, and electricity can arc to nearby objects even without direct contact.

Can a lines company enter my property?

In some circumstances, the regulations allow Westpower to enter land to inspect trees or carry out work.

If access is needed, Westpower will follow the relevant legal requirements and local process. In some situations, relating to treefall hazard removal, Westpower may also ask for the tree owner’s consent to enter the property and remove the tree.

If you have questions about access, please contact Westpower.

Contact us

If you have questions about trees near power lines, please contact Westpower.

General enquiries: 03 768 9300
Email: trees@westpower.co.nz
Faults and emergencies: 0800 768 241