Possums and rats threaten native animal and plant species in the Hūnua Ranges.
In late October 2025 we completed an aerial 1080 pest control operation in the Hūnua Ranges. 1080 is a poison containing sodium fluoroacetate used to control pest species.
The area included:
Visit Our Auckland to read more about the pest control operation.
Monitoring after the operation shows possum numbers dropped dramatically, from 2.2 per cent of traps catching a possum before the operation to just 0.16 per cent afterward.
Rat numbers dropped even more dramatically. Before monitoring began, rat activity was extremely high, with 90 to 100 per cent of tracking devices detecting rats. After the control work, only about 1.3 per cent detected rats.
These results exceeded the targets set in the 2025 operational plan. We aimed to reduce possum numbers to two possums caught per 100 trap checks and three rats detected out of 100 tracking tunnels. Both targets were comfortably met.
At these levels, the forest can recover and native species can thrive.
These targets follow national biodiversity protection and recovery guidelines.
Dogs can return to the on-leash areas of the park from Monday 9 March 2026.
During pest control operations and for four to six months afterwards, dog owners should not bring pets into the parkland. 1080 pellets are highly toxic to animals, particularly dogs.
Monitoring of bait and carcass breakdown is now complete. Results show complete breakdown has occurred so the caution period can be lifted.
For more information on keeping your dog safe, check our dog protection fact sheet.
We follow strict guidelines set out by the Environmental Protection Agency (EPA) and the Ministry of Health (MoH).
We used a two-step process to make sure the operation is as successful as possible.
We used two kilograms of cereal pellets per hectare. To manage the large area and protect water-supply reservoirs, we divided the operational area into two blocks:
During the operation, we:
Before we returned the reservoirs to service we tested the water until sampling showed no traces of 1080.
During the operation, we:
We reopened the parks after we carried out a full track clearance programme.
This operation was in water catchment areas, which required careful planning and working closely with Watercare.
We put measures in place to ensure the ongoing safety of Auckland's water supply, including:
Observe all information and warning signs. It is a criminal offence to remove signs or bait without permission.
Ground-based pest control will be in place on areas of parkland and some surrounding private land that was not treated during the aerial operation.
Always keep your dogs on a leash. This is a requirement within the park at all times.
A Controlled Area Notice is in place across the native forest area of the Hūnua Ranges Regional Park and adjoining DoC-administered lands. This is to protect against kauri dieback disease.
Use hygiene stations to clean and disinfect all footwear and equipment to ensure you do not carry any visible soil into the controlled area.
We have done three aerial control operations in Hūnua, in 2015, 2018 and 2022.
Post-operational monitoring shows our previous operations were very successful.
The number of pest species reduced dramatically, with possum numbers at an all-time low in Hūnua since 2015.
Hūnua's kōkako population has also reacted well to pest control operations.
Population records show an increased number of kōkako:
In 2011 the Parliamentary Commissioner for the Environment released an independent report endorsing the use of 1080. Download the report from the Parliamentary Commissioner for the Environment website.
DoC also looks after large areas of parkland and uses 1080 to manage animal pests.
For more information on the use of 1080, visit the DoC website.
