Feral cats have taken over Australia, including its national parks, and more native species will die off without drastic action, experts say.
A new study by leading environmental scientists has found feral cats have spread across 99.8% of Australia's land mass.
The ocean has not provided much protection either - 80% of the land across all of Australia's islands has been invaded too.
They are sobering statistics in a country that has already lost at least 20 mammals to feral cats, and the bad news does not stop there.
The researchers also found there are just as many feral cats inside national parks and other conservation zones as outside them, meaning they are not much help to native animals that serve as prey.
Lead study author Dr Sarah Legge, from the University of Queensland, says radical new approaches are needed to ensure more native species don't become extinct.
Dr Legge says the spread of feral cats has increasingly pushed land mangers towards expensive conservation measures, such as fencing off areas to create predator-free zones.
Efforts have also been made to establish wildlife populations on islands cleared of feral cats, and she believes island refuges must be expanded in the future.
"The federal government has a target of culling 2 million cats over five years. That's very good, it's very ambitious," she told AAP on Wednesday.
"But it's going to be very important to target cat culling to achieve the greatest benefit for wildlife. If you get rid of cats on larger islands, you can then stop their reintroduction, and then you have a big area that's safe for wildlife."
Australia's feral cat population fluctuates between about 2 million, in lean times, and 6.3 million when there has been good rain, and prey is plentiful.
But cats are also prolific breeders, compounding the problem for wildlife managers.
Australia's Threatened Species Commissioner Gregory Andrews agrees a targeted culling program is an essential part of the solution.
"Australia is the only continent on Earth other than Antarctica where the animals evolved without cats, which is a reason our wildlife is so vulnerable to them," he said.
The research, by more than 40 scientists, brought together almost 100 different studies on Australia's feral cat problem. It was funded by the Australian government to better inform management plans and has been published in the science journal Biological Conservation.
