Climate change migration from northern Australia is well underway, particularly amongst people with the resources to move, Australian National University researchers say.

The Territory's oppressive heat - its tropical and central Australian dry versions both - could lead to health workforce shortages in rural and remote communities, which already struggle to attract and keep doctors.

"The warming climate is the biggest threat to health in the nation," Alice Springs doctor Simon Quilty told AAP.

"Not only does heat kill but it could decimate our rural health workforce and worsen existing healthcare inequity in places that are the most vulnerable to extreme heat."

Researchers found climate change was already impacting patient health, with many doctors saying it's likely to get much worse as more extreme heat events and bushfires occur.

More than 84 per cent of doctors surveyed said rising average temperatures, heatwaves, drier summers and water shortages were likely to or already stressing people's health.

While 85 per cent said climate change was impacting or likely to impact patient health and over three-quarters said it was already causing or likely to cause parts of the NT to become uninhabitable.

One-third said warming had prompted them to consider or likely to cause them to consider leaving the Territory.

"This is not just about doctors leaving, no one wants to raise their kids where it's too hot to play outside or where the town water supply might dry up," Dr Quilty said.

"The NT already has the greatest health inequity of any state of Australia and climate change is rapidly compromising the few gains that have been made."

He's calling on the federal government to adopt a comprehensive national plan for health and climate change to secure the medical workforce in locations with hotter, more extreme climates.

"We must address the need to bolster the workforce for remote and Indigenous communities who are at particular risk," he said.

"Health care workers overwhelmingly understand that climate change is a public health emergency and is already impacting human health."

Researchers surveyed 362 NT doctors. There are about 1300 currently working there, with only half permanently placed.

The NT experienced its fifth warmest year on record in 2020 with much warmer than average temperatures across the entire Top End, according to the Bureau of Meteorology.

Every month except May and December recorded above-average maximum and mean temperatures. Rainfall for the year was marginally below the long-term average.

The Territory is Australia's most remote and sparsely-populated jurisdiction spanning 1.42 million square kilometres.

Indigenous people make up about 30 per cent of its population, 10 times the national average.

They experience much poorer health outcomes with a life expectancy of 66[?]6 years for men and 69[?]9 for women, compared to the non-Indigenous average ages of 78[?]1 and 82[?]7 years.

The research was published in The Lancet Planetary Health.

Australian Associated Press