Australia has the worst rate of animal extinction in the world, and a new study shows it's getting worse.

A three-year national review has found that Australia’s mammal extinction rate is higher than previously thought, and will increase rapidly unless there's a plan to protect all native species.

The Action Plan for Australian Mammals draws on the contributions of more than 200 experts.

It found that more than 10 per cent of the country’s endemic species have become extinct since European settlement, and a further 20 per cent of land mammals are threatened.

But there is hope. The Australian Wildlife Conservancy is building exclusion zones against one of the main culprits - feral cats.

CEO Atticus Fleming says it's estimated there are 15,000,000 feral cats in Australia, and each of them kills around five native animals a night.

He says sanctuaries established by the AWC show populations of native animals bounce back after feral animals are eliminated.

AWC is the largest private owner of land for conservation in Australia, protecting more than three million hectares in the Kimberley, Cape York, Lake Eyre and the Top End.