An inquiry into koala populations and habitat in NSW is expected to hear evidence that more than 2000 of the native Australian marsupial may have died on the state's north coast in recent bushfires.

The state parliament's upper house inquiry will hold an urgent hearing on Monday to discuss the extent of damage to the koala population from bushfires.

Thousands of hectares of koala habitat across northern NSW and southeast Queensland have been destroyed in the recent bushfires.

Koalas are listed as vulnerable in Queensland, NSW and the ACT, largely a result of habitat clearing.

Sharni the koala was one of many treated for burns during bushfires on the NSW north coast

Thousands of hectares of koala habitat across northern NSW and south-east Queensland

On Sunday evening, the Rural Fire Service said there were 91 bush and grass fires in NSW, 48 of which were not contained.

North East Forest Alliance president and ecologist Dailan Pugh is expected to give evidence on Monday that more than 2000 koalas may have died and up to one third of koala habitat on the state's north coast may have been lost in the fires.

Port Macquarie Koala Hospital president Sue Ashton in October estimated at least 350 koalas would have died in a bushfire in Crestwood, on the state's mid-north coast, based on a predicted 60 per cent mortality rate.

Greens MP Cate Faehrmann, chair of the inquiry, said the loss of koalas should be a wake-up call.

'Today's hearing is timely and necessary. We will be hearing from some of Australia's leading experts on koalas, bushfire and climate change,' Ms Faehrmann said in a statement on Sunday.

Port Macquarie Koala Hospital's clinical director Cheyne Flanagan (left) will give evidence at the NSW parliament's upper house inquiry, which starts on Monday

More than 2000 koalas may have died and up to one third of koala habitat on the state's north coast may have been lost in the fires. Paul the koala (pictured) was among those injured

Port Macquarie Koala Hospital's clinical director Cheyne Flanagan and Indigenous fire practitioners are also due to give evidence, as well as representatives of the National Parks and Wildlife Service and the NSW Department of Planning, Industry and Environment.

'We will also hear recommendations that must be urgently taken to ensure these fires don't lead to the irreversible decline of koalas in NSW,' Ms Faehrmann said.

'Hearing that we have lost up to a third of koala habitat and more than 2000 koalas on the North Coast is utterly devastating and should be a wakeup call for this government that they must take action to protect koala habitat.'