Managing trees is a community responsibility. Working together, we can keep trees clear of powerlines, reduce the number of unexpected power outages and keep everyone safe.

You may not know it, but as a property owner, you are responsible for keeping the trees growing on your property clear of overhead power lines and underground cables. The Electricity (Hazards from Trees) Regulations 2003 set out your obligations as a tree owner and prescribe the minimum safe distances for trees growing near network power lines.

The regulations

The regulations include:

  • Any tree or vegetation that is considered a risk to our power equipment
  • Minimum safe distances between trees and power lines (Growth Limit Zones) 
  • Responsibilities on tree owners and line owners for ensuring that clearances are maintained  
  • Setting out the penalties that each party faces for failing to comply with the regulations
  • Outlining the arbitration process for handling disputes between tree owner and line owner 

What are the different zones?

Growth Limit Zone: The minimum distance that a tree must be kept clear of overhead power lines  

Notice Zone: Trees must be cut back so that they are outside of this zone 

Professional Only Zone: By regulation, only qualified and approved utility arborists are allowed to trim trees within 4 metres of a power line.

Fall Hazard Zone: Trees present a hazard if they fall and damage power lines. A tree’s fall hazard zone is the height of the tree plus 4 meters.

What are the minimum safe distances?

Overhead Line Voltage Growth Limit Zone (GLZ) Notice Zone 

The size of the Growth Limit Zone varies depending upon voltage level: 

Overhead Line Voltage Growth Limit Zone (GLZ) Notice Zone
Power lines (230-400 V) 0.5m 1.5m
High voltage lines (6.6 kV) 1.6m 2.6m 
High voltage lines (11kV) 1.6m 2.6m 
High voltage lines (33 kV) 2.5m 3.5m
High voltage lines (50-66 kV) 3.0m 4.0m 
High voltage lines (66 kV or more) 4.0m 5.0m

Underground Cable Growth Limit Zone (GLZ) Notice Zone 

Cable voltage Tree root Growth Limit Zone (GLZ) Notice Zone
All voltages 0.5m 1.5m 

Check that your trees are outside the fall hazard zone and consider trimming or removing them to avoid causing damage and incurring future costs.  Please note your Trim Notice will include the required clearance distance from your tree.

For more information please check the Electricity (Hazards from Trees) Regulations 2003.

Notice, growth and fall zones

Diagram showing the growth limit zones for trees growing near power lines and power poles. There is the outer ring which from that point inward, is a professional arborist only zone, the middle ring is when you'll receive a notice from us and the inner circle is the growth limit zone.
Diagram showing the growth limit zone of tree roots growing near underground cables.
Diagram showing examples of a tree fall zone when close to a powerline.

Your responsibilities

Trimming and felling trees around power lines is very dangerous and could result in serious injury from electric shock or electrocution. For this reason, by regulation, only qualified and approved utility arborists are allowed to trim trees when they are within 4 metres of a power line.

If all parts of the tree are more than 4 metres away from overhead lines, you can safely trim the tree yourself or hire an arborist to do this for you. All care must be taken to prevent any part of the tree coming into contact with any power lines.

If any part of the tree is within 4 metres of the line or you have received a notice from us, you'll need a professional arborist authorised to work near power lines for your safety and the safety of others. Delta and Asplundh are our arboriculture Approved Contractors.

Penalties for non-compliance

Before we take any further action we will issue a Final Notice to remind you of your obligations and your final date for action. Doing nothing does not remove your responsibility under the regulations.

If you do not comply with a notice within the time specified, then you could be:

  • Fined up to $10,000
  • Held liable for costs of repairs if our lines or equipment are damaged by your tree
  • Held liable for damage caused by broken power lines
  • Held liable for damage caused by any resulting power surges affecting others


If you believe that the tree does not pose a hazard to power lines, you can apply for dispensation within 5 working days of receiving this notice. If you’re unhappy with the dispensation decision, you can apply for arbitration within 5 working days of any dispensation decision. Information on how to apply for dispensation or arbitration is on our tree FAQ