But the Invasive Species Council of Australia has put the required budget in the hundreds of millions, calling on the federal government to help bankroll states' pest control efforts.

Chief executive Andrew Cox said sending in the army to cull feral animal numbers wasn't an option.

"I think what's missing is the resources to mobilise the experts," Mr Cox told reporters in Canberra on Thursday.

"It's a national problem. And all parties need to be working together."

The council's indigenous ambassador Richard Swain said feral animals - like horses, foxes or cats - would bounce back from the fires better by outcompeting or eating native species.

Mr Swain, who has also been volunteering as a firefighter, said Australians needed to work together to protect their heritage.

"Whether you're 100 years old or 100 seconds old, if you're an Australian, you've seen nothing but decline in our natural world," he said.

"We need the best science, we need to bring aerial culling in, we need to stop protecting things like feral horses within our national park."

More than one billion animals are thought to have perished in the unprecedented bushfires across Australia, but the final extent won't be known for some time.

The federal government has put an initial $50 million into a wildlife and habitat recovery package, with decisions on its use steered by Threatened Species Commissioner Sally Box.

"We certainly know that after a fire that our native species are more vulnerable to predation by cats and foxes. Cats will prowl the edges of a fire scar looking for native animals," Dr Box told ABC radio on Thursday.

"Native animals will have lost much of their shelter, their cover that they can hide under after a fire, so it does make them more vulnerable to predation."

Controlling herbivores and weeds is also a priority, she added.

"The fires are still going and so there's more burning to come, sadly," Dr Box said.

"Fires affect the landscape differently, it will be more intense in some places than in others. And also different species have different vulnerabilities to fire."

A large number of threatened species were in the path of the fires in southeastern Australia.

Dr Box is particularly worried about the dunnart and black glossy cockatoo populations on Kangaroo Island, long-footed potoroos in East Gippsland as well as threatened plants.

Koalas are at risk of being listed as endangered following the bushfires, with habitats lost across Australia.

She was relieved to know NSW firefighters had saved the last of the so-called "dinosaur trees" remaining in the wild, in Wollemi National Park.

At a meeting with Dr Box and Environment Minister Sussan Ley on Wednesday, wildlife experts pleaded with the government to better fund the sector, saying efforts to help threatened species recover will cost billions.

Australian Associated Press