Cat owners will need to micro-chip their cats or Auckland Council will put them down under its proposed new pest eradication programme.
But the plan to expand the Council's cat cull is under fire, with cat lovers calling it "absolutely ridiculous".
The Council is currently reviewing its Regional Pest Management Plan, and proposes redefining the definition of a pest cat to include any that aren't microchipped or identifiable as being owned.
Any cat caught in an "ecologically significant site" without a microchip could be put down, Fairfax reported.
Auckland Council biosecurity manager Phil Brown told Tuesday's environment and community committee this was the next step forward.
"It's not a reactive programme," Fairfax reported Mr Brown as saying.
"It will be well planned at specific sites of ecological significance where rats, possums and other pests are also being managed."
However Cat Society of New Zealand president Anne Batley-Burton has attacked the Council's "ridiculous" idea.
"For a start the only reason they want to microchip cats is for revenue gathering, and it's a licence for the Council to kill strays," she told RadioLIVE on Thursday.
"It's a complete waste of ratepayers' money as well, all these rangers and people running around looking for stray cats."
She says stray cats aren't more likely to kill native animals than people's pets and the Cat Society is going to fight the Council on the issue.
"We are most definitely, we're already making a lot of moves in this area already," she says.
The public will be allowed to comment on the plan in 2018.