Trees growing into power lines cause outages, damage equipment and prevent our crews from repairing equipment quickly, delaying getting the power back on to customers. Vegetation that gets too close to power lines can create a fire hazard. Some children love to climb trees and this is especially dangerous if there are power lines nearby.

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 (Tree Regulations) set out your obligations as a tree owner and prescribe the minimum safe distances for trees growing near network power lines.

We’ve provided a general summary here on your responsibilities as a tree owner, how to keep safe when clearing trees near powerlines and where to go for help in managing trees. See our Tree Safety Brochure (PDF) for details.

If you see a tree or other vegetation growing into Aurora Energy power lines, please report it and we will send someone out to inspect it. You can get in touch with us here

If a public site (not near power lines) requires immediate vegetation clearance, please contact your local council.

Keeping your trees away from lines

As tree owner, you are responsible for keeping trees clear of power lines. Where we identify trees growing close to our power lines, we are required, by law, to take action to ensure trees are kept clear of the required clearance by either trimming them or notifying the tree owner that they are required to trim their trees. 

Growth Limit Zone

Growth Limit Zones are the minimum distances any tree, or part of a tree, must be kept away from an overhead power line or underground cable. You must keep your trees and vegetation clear of the Growth Limit Zone around an overhead network power line. The size of the Growth Limit Zone varies depending on the voltage of the power lines. (The Tree Regulations only cover network lines and not your service line).

We suggest that you keep trees well outside these distances to allow for tree growth and severe weather conditions as wind and snow can cause branches to come into contact with overhead power lines. We inspect our lines and let tree owners know when their tree/s are encroaching the Growth Limit Zone.


Tree B is in the Growth Limit Zone and will need to be cut or trimmed by an authorised arborist within the prescribed timeframe. Both Tree A and Tree B are within the Professional Only Zone and need an authorised arborist to trim.



Overhead Line Voltage

Growth Limit Zone (GLZ)

Notice Zone

Power lines (230-400 V)



High voltage lines (6.6kV)



High voltage lines (11kV)



High voltage lines (33kV)



High voltage lines (50-66kV)



High voltage lines (66kV or greater)





Underground Cables                              

Growth Limit Zone (GLZ)

Notice Zone

All voltages

0.5m for tree roots


Keeping safe when trimming trees near power lines

  • Power lines are not insulated so never touch a power line.
  • Always assume that a power line is live and dangerous.
  • Do not trim or cut down trees near power lines or within falling distance of power lines and structures.
  • Stay clear of power lines when removing any object caught in a tree.
  • lf a tree branch breaks off and lands on a power line, call your electricity retailer immediately.
  • Make sure your children stay safe and do not climb trees that are anywhere near overhead power lines.

Trimming or felling trees around power lines is very dangerous and could result in electrocution or serious injury from electric shock. For this reason, by law, only qualified and approved utility arborists are allowed to trim trees within 4 metres of a power line. This is known as the Professional Only Zone.

  • 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 trim the tree for you.
  • If any part of the tree is within 4 metres of the line or you have received a trim notice from us, you’ll need a professional arborist authorised to work near power lines – for your safety and the safety of others.

Approved tree contractors 

By law, only qualified and approved utility arborists are allowed to trim trees within 4 metres of a network power line. Aurora Energy’s approved tree contractor is:

  • Delta - freephone 0800 433 582 or email Delta to organise a trim near power lines.

Hazard Warning Notice

If your tree encroaches inside the Notice Zone, Aurora will send you a Hazard Warning Notice advising you that the tree is about to reach the Growth Limit Zone and the options you have. The notice gives you the opportunity to return to us a No-interest Notice which means that you have no objection to the tree being removed at Aurora Energy's cost. The notice will also advise you of your rights to object to the tree being trimmed, for example where the tree is of amenity value and/or has historical or cultural importance.

Cut or Trim Notice

If your tree encroaches inside the Growth Limit Zone, Aurora Energy will send you a Cut or Trim Notice, which will advise that the tree must be cut or trimmed within a prescribed timeframe (between 10 and 45 working days depending on the circumstances). You can arrange for Aurora Energy to do the work, or for some other properly qualified party to do so. The notice also gives you the opportunity to return to us a No-interest Notice, or to express your interest in the tree and objection to having it trimmed or removed. If you have not removed the hazard or lodged an objection within the time limit, Aurora Energy may arrange for the tree to be trimmed or removed at your cost.

The first cut is free

With one exception, the cost of keeping your trees clear of Aurora Energy's power equipment is yours. The exception is the first free trim provided for by the Tree Regulations. Where there is no record of a previous free trim, then Aurora Energy will pay for the first trim, or for the tree to be removed. We will require your signature on the Cut or Trim Notice approving access to your property before we carry out the work.

The first free trim does not apply to:

  • private service lines (usually the power line connecting your house to the street). We provide a free temporary disconnection service so you can safely trim trees from the service lines on your property
  • shelter belts or plantation forests.

We use Delta’s qualified tree management service to do this work. In some cases, proper tree trimming techniques may require that the tree is cut back further than the Notice Zone in order to protect the health of the tree. Our arborists will talk to you about this before starting work. 

To organise a first trim, contact Delta.

Subsequent trimming is at the tree owners cost

After the first cut, the tree owner is responsible for any subsequent trimming and for the cost of that work. If you are required to trim a tree on your property, you must:

  • arrange for the tree to be trimmed within the prescribed timeframe specified in the Cut or Trim Notice
  • employ an approved utility arborist to carry out the work
  • provide Aurora Energy with at least three working days' notice of the work and advise us of the time and location of the works so we can ensure that the activity is adequately monitored and safe.

Non-compliance with a Cut or Trim Notice

If you do not comply with a Cut or Trim Notice within the time period specified, then you could be fined up to $10,000. You could also be held liable for costs of repairs if our lines or equipment are damaged by your tree and for damage caused by broken power lines and/or by any resulting power surges affecting third parties.

Declaring ‘no interest' in trees on your property

If you do not want to be responsible for keeping a tree on your property trimmed in accordance with the Tree Regulations, you can declare ‘no interest’ in the tree at any time. To declare ‘no interest’, the tree has to be naturally sown or, at the time of planting, the current or previous property owner must have reasonably believed that the tree, when fully grown, would not interfere with any power lines or electricity conductor.

To declare ‘no interest’ in a tree, you must notify us in writing. If you have already received a Cut or Trim Notice in respect of a tree that you wish to declare ‘no interest' in, then you must provide notice to us within 10 working days.

If we receive a ‘no interest' tree notice, we may remove or trim the tree to an extent determined by us. Please note that the tree may be removed rather than trimmed if it is likely to cause a continuing problem.

If the tree does not meet the criteria set out in the Tree Regulations then the ‘no interest' tree notice will have no effect and your obligations as a tree owner will continue to apply.

Plan before you plant

Plan your garden, shelter belt and forest layouts before you plant and consider tree species and growth rates. Allow for the position of trees and future growth in relation to overhead power lines and underground cables. By choosing wisely you can avoid the safety risks and the future maintenance costs of trees growing too close to power equipment.

Make sure you know exactly where all underground cables are, and do not dig holes within 4 metres of them. Check before you dig.

Before you plant a tree, it is important to check that the mature growth height of trees and shrubs will not encroach on overhead power lines. Early planning will avoid trees having to be trimmed or removed prior to maturity later on – saving you time and money. Check out our tree planting guide for suggestions (PDF).

If you plan to plant a tree near power lines, consider low-growing species that are below 4 metres maximum in height. Trees planted directly under lines should be below 2 metres maximum in height.

Where trees have been removed, you can stop regrowth or sprouting by applying environmentally-friendly herbicides to the stumps. It may then be possible to plant other power line-friendly shrubs in their place.

For advice on native species most suitable to your region or habitat, contact your local nursery, arborist or contact the Otago Regional Council.

Fall hazard zone

Tree owners should be aware that trees present a hazard if they fall and damage power lines. The closest a tree can be located is calculated on the basis of the height of tree plus 4 metres. Check that your trees are outside the fall hazard zone and consider trimming or removal to avoid causing damage and incurring future costs.