Australia moved on Monday to protect its most vulnerable koalas, listing the much-loved furry tree-dwellers as a threatened species in parts of the country.

Environment Minister Tony Burke said the most at-risk koalas needed to be on the national list of threatened species, and populations in New South Wales, Queensland and the Australian Capital Territory would be listed as vulnerable.

"Koalas are an iconic Australian animal and they hold a special place in the community," he said.

Burke said while some koala populations were under serious threat from habitat loss and urban expansion, as well as cars, dogs and disease, in other areas they were thriving to the point they needed to be controlled.

"In fact, in some areas in Victoria and South Australia, koalas are eating themselves out of suitable foraging habitat and their numbers need to be managed," he said.

"But the Queensland, New South Wales and Australian Capital Territory koala populations are very clearly in trouble, so we must take action."

An official report issued last year found the sleepy, furry marsupials were under increasing threat and should be considered a vulnerable species, with habitat loss seeing their numbers plunge.

Believed to number in the millions before British settlers arrived in 1788, the hunting and slaughter of the animals for their furs in the 1920s devastated the species in some areas.

Public outrage over the killing of the big-eyed "bears" put an end to the practice but numbers have never fully recovered, with estimates on the population varying from several hundred thousand to as few as 43,515.

Environmentalists have for years been pushing for greater protections for the koala, which sleeps about 20 hours a day and eats only the leaves of the eucalyptus tree.

University of Tasmania zoology professor Chris Johnson said the government's move was sensible.

"The northern and southern populations are now basically separate," Johnson said, saying they almost needed be considered as different species.