Biosecurity considerations for walking and tramping

Walking and tramping are great ways to enjoy New Zealand's environment, but you need to make sure you don't damage our environment while you take part. Find out how you can help protect our great outdoors.

Protect our environment when you're outdoors

Check, clean, dry to stop the spread of pests

Freshwater pests, like didymo, spoil river activities for people and can damage the habitats of freshwater plants and animals. They can be spread by a single drop of water or plant fragment. It's everyone's responsibility to slow the spread of freshwater pests.

When tramping and walking you need to:

  • Check – remove all obvious debris from boots and items that have been in contact with the water.
  • Clean – spray boots and socks for at least one minute, or until completely soaked in a 10% biodegradable detergent solution (1 tablespoon of detergent for a 250ml spray bottle)
  • Dry – drying will kill didymo, but even slightly moist items can harbour pests for months. To make sure didymo cells are dead, the item must be completely dry to the touch, inside and out, then left dry for at least another 48 hours before use.

Boots and equipment can spread freshwater pests

Freshwater pests, like didymo, oxygen weed and hornwort, are a serious threat to our rivers, streams and lakes.

didymo also known as
Didymo can be spread by just one drop of water.

They can spread quickly, and destroy the environmental, recreational and aesthetic values of our waterways.

Some freshwater pests are microscopic and not visible to the human eye. You could be spreading pests with just one drop of water.

Taking steps to prevent the movement of pests is especially important if you're crossing more than one stream or river.

Cleaning your tramping equipment

The thicker and denser your tramping equipment, the better it will be at holding moisture. Thick materials are slower to dry out, and more difficult to decontaminate completely with cleaning solutions.

When cleaning equipment, you should:

  • remove all obvious debris from boots and items that have been in contact with water
  • spray thick, dense or porous material for longer than other items to make sure the cleaning solution has soaked right through
  • choose a decontamination solution that will not badly affect your equipment or the environment 
  • dispose of cleaning waste well away from waterways
  • pay special attention to cleaning when crossing into a new catchment, and after the last crossing of the day.

Safety when cleaning

Your personal safety is important — always consider weather conditions, slippery rocks and detergent before decontaminating your equipment.

The South Island is a controlled area

The South Island is a controlled area for didymo. This makes it a legal requirement to clean all gear used in the water before going from one waterway to another.

Take extra care on the Milford Track

Didymo is present in Lake Te Anau and Lake Manapouri. To limit the spread of didymo, Milford Track walkers need to bring dry clothing and boots. If boots and socks are damp you will need to be disinfect them before leaving for the track.

Cleaning gear is provided at some huts but you are encouraged to carry your own supplies. You should check, clean, dry before going to Fiordland.

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Specific freshwater pests

These are the freshwater pests we are most concerned about:

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Help prevent the spread of kauri dieback

kauri tree with kauri dieback disease
All kauri trees are at risk.

Kauri dieback is a fungus-like pathogen that kills both kauri trees and seedlings. We need to act now to protect our kauri forests from this disease.

We have no treatment or control tools, the only way we can save our kauri forests is to contain the disease in existing locations and stop the spread into healthy areas.


When visiting areas with native forest in the upper North Island:

  • clean your footwear and other gear before you enter and as you leave the area
  • stay on walking tracks
  • keep off kauri roots (kauri tree roots can grow outwards 3 times as far as its branches).

Most significant kauri forests have signs at the entry points and exits to let you know that you need to take care to not spread kauri dieback.

How to identify a kauri tree

Kauri trees have greyish bark and leathery leaves.

Call the hotline if you see signs of the disease

If you think you have seen diseased kauri on public or private land, phone the Kauri Dieback Hotline on 0800 NZ KAURI (69 52 874). 

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Keep watch when you are in the outdoors

When you are walking or tramping in New Zealand, be on the lookout and call 0800 80 99 66 if you see:

  • an animal pest
  • a plant pest
  • signs of plant or animal disease.

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Who to contact

If you have any questions about preventing the spread of pests and diseases when walking and tramping, call MPI on 0800 00 33 33.

Last reviewed: