Nearly three billion animals were killed or displaced by Australia's unprecedented 2019-20 wildfires in "one of the worst wildlife disasters in modern history", according to a report released Tuesday.

The study by scientists from several Australian universities said the wildlife hit included 143 million mammals, 2.46 billion reptiles, 180 million birds and 51 million frogs.

While the report did not say how many animals died because of the fires, the prospects for those that escaped the flames "were probably not great" due to a lack of food, shelter and protection from predators, said Chris Dickman, one of its authors.

A kangaroo jumps in a field amidst smoke from a bushfire in Snowy Valley on the outskirts of Cooma in January
A kangaroo jumps in a field amidst smoke from a bushfire in Snowy Valley on the outskirts of Cooma in January AFP / SAEED KHAN

The fires ravaged more than 115,000 square kilometres (44,000 square miles) of drought-stricken bushland and forest across Australia in late 2019 and early 2020, killing more than 30 people and destroying thousands of homes.

It was the broadest and most prolonged bushfire season in modern Australian history, with scientists attributing the severity of the crisis to the impacts of climate change.

An earlier study in January estimated the fires had killed a billion animals in the hardest-hit eastern states of New South Wales and Victoria. But the survey released Tuesday was the first to cover fire zones across the continent, said lead scientist Lily van Eeden of the University of Sydney.

Results from the survey were still being processed, with a final report due to be released late next month, but the authors said the number of three billion animals affected was unlikely to change.

An animal rescue worker holds a baby koala affected by the bushfires on Kangaroo Island
An animal rescue worker holds a baby koala affected by the bushfires on Kangaroo Island AFP / PETER PARKS

"The interim findings are shocking," said Dermot O'Gorman, CEO of the Australian branch of the World Wide Fund for Nature, which commissioned the report.

"It's hard to think of another event anywhere in the world in living memory that has killed or displaced that many animals," he said.

"This ranks as one of the worst wildlife disasters in modern history."

The plight of Australia's popular koalas during the fires garnered international media attention, with thousands of the tree-dwelling marsupials believed to have perished.

But a government report early this year cited 100 other threatened native plant and animal species that had lost more than half their habitat to the blazes, raising the prospect of far greater losses.

Scientists say global warming is lengthening Australia's summers and making them increasingly dangerous, with shorter winters making it more difficult to carry out bushfire prevention work.

The report released Tuesday was drawn up by scientists from the University of Sydney, University of New South Wales, University of Newcastle, Charles Sturt University and conservation group BirdLife Australia.

Australia