Cats from nearby homes have reportedly died in or around animal enclosures at Wellington Zoo.
Last week, Kobe the cat walked from his home at the nearby Melrose Crescent into Wellington Zoo.
His body was found in an animal enclosure.
Zoo chief executive Karen Fifield told Fairfax he was "obviously killed by one of the animals" but she didn't want to go into too much detail.
"It wasn't in with a pygmy marmoset for example," she said.
And in February, a cat named Henry, whose owners also live on Melrose Cres also died on the zoo grounds.
Fifield said that during her 11 years working at the zoo, three cats had died in or near animal enclosures.
"We've done all we possibly we can, as I said, in terms of the new perimeter fence and advocating to keep cats inside at night," she said.
"If you've got an inquisitive cat, it will find its way through."
She empathised with their owners.
"We're animal people, and we know that people love their pets. We feel terrible for the people who this happened to," she said.
Henry's owner, who did not want to be named, told Fairfax the zoo had called to break the news.
"My husband took the call, and I instinctively knew it was about Henry," she said.
"I asked if he was alive ... and he shook his head. I just burst into tears."
The woman told Fairfax she had emailed zoo staff about gaps in the zoo fence, months before Kobe's death.
"We thought that they would at least put a netting behind it but nothing happened," she said.
"I would be mortified if our cats got into the kiwi or penguin enclosure, none of which is fenced off, and attacked their wildlife. So, I don't know why it's not a priority for them."