The northern bettong one of the "endangered" species is now a "critically endangered" species

A truffle-eating Australian marsupial known as the rat kangaroo has suffered a dramatic population decline and could become extinct without urgent action to save the species, a report warned today.

The World Wildlife Fund said only two populations of the northern bettong remained in the wet coastal tropics of northern Queensland state, numbering at most 2,500 individuals, down 70 per cent in the past 30 years.

The nocturnal, rabbit-sized bettongs are at risk from feral cats, land-clearing and wildfires, which have become more frequent and fierce in Queensland due to climate change.

"We know particularly with climate change a massive wildfire could be just around the corner," said Tim Cronin, WWF's senior manager for species conservation in Australia.

"Any situation where you have one population isolated and that's all you have in the wild, it puts you at a really high risk."

Cronin said it was critical to establish an "insurance population" of the northern bettong, protected from pests and fire, and consider raising the species' status from "endangered" to "critically endangered".

"It's not too late for the northern bettong, but our window of opportunity for action is closing fast," he said.

The northern bettong is one of the main animals which eat truffles, dispersing truffle spores across its habitat and maintaining a delicate ecological balance.

"It plays a really unique role in maintaining ecological function in the vegetation. So if we lose it and other species like it we could be looking at ecological collapse," Cronin said.