Nearly half a billion animals are feared dead in the wildfires burning across Australia, including a third of the koala population in their main habitat in the state of New South Wales.

Ecologists at the University of Sydney estimated that 480 million mammals, birds and reptiles died in the blazes that have swept the nation since September.

As several states sweltered through record-breaking heatwaves and dense smoke, images of charred koalas, fleeing kangaroos and dead birds appeared on social media:

The estimated death toll included up to 8,000 koalas, according to the federal environment minister Sussan Ley, who said in an ABC Radio interview Friday that up to 30 percent of the species in New South Wales may have been wiped out. The states mid-north coast is home to a significant portion of the nations koalas, with an estimated population of between 15,000 to 28,000.

Ley said that 30 percent of this key habitat was also destroyed.

Well know more when the fires have calmed down and a proper assessment can be made, she said.