Bodies of sea birds are "piling up" in Mount Maunganui due to domestic cats hunting them.
The Western Bay Wildlife Trust is urging cat owners to keep their felines inside at night as the trust finds bodies of diving petrels "on a daily basis".
Trust co-founder and trustee, scientist Julia Graham, said cats were "a huge predator" and she was "very concerned" about the impact they were having on native species on Mauao and Moturiki Island.
She wants a ban on keeping cats around those areas.
Graham said Mauao and Moturiki Island were "special ecological areas" where threatened species were "trying to breed and live".
Petrels were "very easy to catch" because they had not evolved around mammal predators and spent most of their time at sea, she said.
"They don't have any fear – they just don't know what's coming for them.
"Once a cat finds a good hunting ground like that...they just keep coming back."
Graham said the issue had been going on for "years" and trail cameras showed the impacts cats had on birds, including penguins.
"It's about raising public awareness," she said.
"These are domestic pet cats – they're not feral cats."
Graham said it was important to keep cats locked in at night because this was "prime hunting time".
"[Cats] can travel for long distances. It's not the people who are directly opposite Moturiki Island… it's in the surrounding blocks."
Graham said the trust was working on a submission to Tauranga City Council about cat control.
"Ideally any household living within a certain radius of an area like Mauao or Moturiki Island would eventually not be allowed cats," she said.
In addition to cats being kept inside at night, she wanted pet cats registered and micro-chipped.
"That way, if we do manage to catch one [the council] can track them down to an owner."
The trust needed more funds for cameras to monitor what happened inside penguin burrows as this provided "crucial data" to help protect the species, Graham said.
"Some of these penguins are still the Rena penguins that we saved back then."
Tauranga City Council ranger Josh Clark said the council had set live traps on Moturiki Island and would be speaking to local residents.
"When we became aware of a cat hunting on Moturiki we put out multiple live traps, using different types of lure. This has unfortunately not always been successful in catching cats," he said.
The live traps could not be triggered but were installed to get the cat used to the trap and gain its trust by placing lures, he said.
"Once our camera detects this cat entering, the trap will then be correctly set."
The council would also do a letter drop to inform immediate residents of the issue and ask them to keep their cats inside at night, Clark said.
"Responsible cat ownership is a major factor when it comes to wildlife protection.
"We must realise that we are co-living in the same habitat as these native and protected species and we must act to protect them from predation."
Clark said any changes to by-laws relating to cat control would be the "ideal situation near any high-value ecological site" and would need to be introduced through changes to legislation.