Approving new and expanding mine leases would be another nail in the coffin for the koala, environmental groups say.
In a letter to federal Environment Minister Tanya Plibersek, 50 environmental organisations have urged the rejection of proposed mining developments in Queensland and NSW.
The letter asks Ms Plibersek to put a moratorium on any projects that would mean clearing of koala habitat and to commit to phasing out fossil fuels.
The Australian Conservation Foundation's climate and energy program manager Gavan McFadzean said the koala's existence was at risk if proposed new coal mines and expansions were approved.
"It's another nail in the coffin of the koala and other iconic Australian species which are hurtling towards extinction," he told AAP.
"It's hard to imagine a more shocking indictment on Australia's management of its endangered species than to see the iconic koala go extinct, partly because Australia continues to approve and open up new coal projects that are clearing their habitat."
There are 40 proposed new coal mining projects across Queensland and NSW, awaiting government approval, the letter to Ms Plibersek says.
"More than half of these coal projects propose to destroy koala and greater glider habitat," it says.
A study, released in early June, found 42,000 hectares classified as potentially suitable koala habitat would be under threat from 12 proposed mining developments in central Queensland.
The study, commissioned by Lock the Gate Alliance and Environmental Advocacy Group Central Queensland found koala habitat in the Bowen Basin area had declined by more than 40 per cent from colonisation to 2020.
Lock the Gate Alliance national coordinator Ellen Roberts said the federal government cannot keep approving coal mines if they were serious about protecting koala populations.
"The koala was nominated as a mascot for the 2032 Olympic Games because it's so treasured and so loved by Australians, and so recognised internationally as one of our mammal icons," she said.
"If we want to keep putting koalas out there as a national icon on the public stage we need to make sure we're doing everything to protect it, otherwise by 2050, koalas will be functionally extinct in the wild, which is just a devastating reality for Australians and the rest of the world."