A national study by the CSIRO this week revealed that feral cats were targeting 100 species of Australian mammals, with extinction rates up 40 per cent.

Birds, bandicoots and even quolls are believed to be struggling against the predators.

Professor Johnson said he was not surprised by the statistics, since feral cats were an "established" Tasmanian environmental problem.

"It's impossible to eradicate cats unless they're on a small island, as seen with Macquarie Island," he said.

"There's just too many in Tasmania and on the mainland.

"Although no species have yet become extinct because of them, it's very possible it will occur in the future."

Professor Johnson said while there was no hope of ridding the state of the pests, residents could still do their bit to help manage the issue.

"People can look after their own cat and participate in sensible pet management.

"Don't let them roam around at night - that's significant.

"Unfortunately it doesn't make much difference to wild cat numbers in the bush, however.

"They are really well established and they don't depend on the input of the domestic cat population." Tasmania Zoo owner Dick Warren said he had battled feral cats for several years.

"It's just getting bigger and bigger and bigger," he said.

"They've targeted our birds, our pet rabbits, even a joey."

Mr Warren urged residents to take their unwanted cats to Tasmania Zoo to be rehomed, rather than release the animals into the wild. "At least get them micro-chipped and get permission from the council before you breed them," he said.