Any cat found in an "ecologically significant site" without a microchip could be euthanised if the regional plan goes ahead.

Cats without microchips found roaming in sensitive environments will be killed under Auckland Council's new pest eradication programme.

Auckland Council is proposing to spend $307 million over the next 10 years to rein in the region's pests and protect its ecosystems and threatened species.

The plan will clarify when a cat is a pest based on whether or not it is micro-chipped, which will help identify stray cats.

SIMON MAUDE/STUFF Auckland councillor Daniel Newman says council should be prepared from a backlash from cat owners.

Any cat found in an "ecologically significant site" without a microchip could be euthanised.

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Auckland Council said approximately one third of cats in New Zealand are microchipped, but there are no Auckland statistics because it is a voluntary procedure.

Auckland Council environmental advisory manager Imogen Bassett told councillors at the environment and community committee on Tuesday that it was a "very polarising issue".

"We've tried to balance people's rights and the value of domestic cats with managing their impacts in high value areas to protect native species," Bassett said.

At the same meeting Auckland councillor Daniel Newman said it would dominate the forthcoming regional pest debate.

"I can understand the value of the proposition here, but I don't necessarily believe that the community itself is going to fully appreciate that," Newman said.

"There's a high premium on the value of the domestic mog." Are you ready for the response from the community?

"The best communication strategy under the sun is not going to allay all concerns."

Auckland Council biosecurity manager Phil Brown said feral cats were already classified as pests, and in many ways the proposed plan represented the continuation of council practise.

"It's not a reactive programme," Brown said.

"It will be well planned at specific sites of ecological significance where rats, possums and other pests are also being managed."

Cats were a danger to the survival of numerous threatened species including black petrel, Cook's petrel, dotterels and kiwi, Brown said.

Globally cats had contributed to 14 per cent of modern bird, mammal and reptile extinctions, and 8 per cent of critically endangered birds, mammals and reptiles globally were threatened by cats, he said.

Cats also carried the parasite responsible for a disease called toxoplasmosis which was responsible for a high number of Hector's dolphin deaths, he said.

Despite not being mentioned anywhere in council's 2015 regional pest management plan public discussion document, cats were the species most submitted on, he said.

The vast majority of those submissions called for enhanced management of cats in order to protect Auckland's native biodiversity, he said.

While preventing cats from invading cat-free nature reserves such as Tiritiri Matangi was a priority there were important sites on the mainland as well, including Shakespear Regional Park, Tawharanui Regional Park, Ark in the Park and the Hunua Ranges.

"We all have our part to play," he said.

Cat owners could be responsible pet owners by de-sexing, micro-chipping and keeping cats indoors at night, especially in areas close to native habitats, he said.

All 21 local boards supported the proposed approach to cat management.

The plan will be open to public consultation early next year.