The pesticide 1080 will be dumped from helicopters on the Hunua Ranges - the source of Auckland's water supply - next winter, Auckland Council has confirmed.
At its meeting today, Auckland Council's Regional Strategy and Policy Committee approved a proposal to manage pests in the 17,000ha park by aerial dropping 1080 pellets.
The method would be used by the Department of Conservation in its $21 million project to knock back pests as part of its "Battle for our Birds" campaign.
The department said its poison project was a response to an increase in predator numbers brought on by "masting year" - where trees were fruiting and making more food for predators.
Masting year was occurring in the Hunua Ranges Regional Park - which supplies 65 per cent of Auckland's water - Auckland Council said.
The park is also home to Auckland's only mainland kokako population and supported the long-tailed bat, hochstetter's frog, kaka, kereru, bellbird and tomtit communities.
Committee chairman George Wood said this was a landmark decision for the future of the Hunua Ranges, and not one that was taken lightly.
"This was not an easy decision and one in which we considered a wide range of views and opinions.
"We have drawn on the experience of other agencies and the expertise of scientists from across New Zealand to make a decision that confronts a very real threat to the Hunua Ranges," he said.
"Throughout this operation, Auckland Council will be looking very closely at the science and the practical implications of the use of 1080 ? we will take these learnings to control pests and ensure that our bush and native wildlife is preserved for the future."
Council would continue to engage with iwi, local residents and landowners, key stakeholders and interest groups as it developed the plan, Mr Wood said. "The decision has been made and councillors have provided some direction for officers, they will now turn their attention to planning the operation ? the future of the Hunua Ranges will be a hot topic for discussion for some time to come."
United Future leader Peter Dunne said the controversy surrounding today's decision emphasised the need for a moratorium on the use of 1080 as a pest control method to better assess its efficiency.
"If 1080 is to be dropped aerially near urban communities or waterways, better information about the long-term effects of 1080 on not just the local bird population, but also human beings, needs to be established.
"In the absence of this, there is a strong risk of adverse public reactions over time making it impossible for any form of intrusive pest control to be carried out."
The operation would be carried out halfway through next year and would only affect the Hunua Ranges, the council said.