A new report from the Nature Conservancy has found that mammal species in northern Australia are in rapid decline and many are at risk of becoming extinct within the next decade.

At least a dozen species are listed as critical or endangered and another dozen are thought to be vulnerable.

Researchers believe the problem is getting worse and feral cats and fire management are largely to blame for the decline.

The head of biodiversity for the Northern Territory Environment Department, Professor John Woinarski, says the mostly small and furry creatures are under immense pressure and in many cases are living on borrowed time.

"When I came here 25 years or so ago it was a paradise for native mammals and that's just not the case anymore," he said.

"It's perplexing. Much of the landscape still looks extraordinarily intact and natural and extensive and beautiful, but some of the species are clearly falling out of that landscape.

"It's been a difficult task for us to figure out what's causing that decline, given the apparent naturalness of landscape.

"We think that the main contributing factors are predation by feral cats and changed fire regimes."

Professor Woinarski says it is one of the region's smaller inhabitants that may be the next victim.

"There's a beautiful rodent called a brush-tailed rabbit rat which is a guinea pig-sized animal but with a beautiful long feathery tail," he said.

"We're witnessing its really rapid decline over the last two decades. It's disappeared from a lot of places where formally it was very common and it's the one I'd pick as the most likely for extinction in the next 10 or so years.

"But there's a range of others which are similarly declining in more or less the same sort of synchrony I guess."

Parks no sanctuary

He says Northern Australia's extensive system of national parks has not offered much protection.

"We used to think conservation would work if you set aside large areas for national parks and that the biodiversity in those parks would maintain itself; that's clearly not the case," Professor Woinarski said.

"Our results are showing that you really do have to intensively manage and manage in a really targeted way if those national parks are to maintain their biodiversity."

He says the national parks do not offer much protection because they are subjected to many of the same threats to biodiversity as are occurring in northern Australia outside parks.

"So in many cases the fire regimes in national parks does require improvement. In many cases the management of cats and other feral animals in national parks is proving to be an extraordinarily difficult problem," he said.

Dr James Fitzsimons from the Nature Conservancy says there have been some positive changes, as traditional Aboriginal fire management practices have been reinstated in some areas.

That has prevented large, uncontrolled bush fires in the dry season but he says more needs to be done.

"There's been a big improvement in these last few years in a lot of places to reinstate some of the traditional fire regimes, but in many places we are still seeing large uncontrolled wildfires," he said.

"The trick will be to get some money into some of those communities to ensure some of the improved fire regimes is occurring to get both better habitat and better range of food for those species as well."

Dr Fitzsimons says there is plenty that can be done to improve fire management practices, but he says the problem of feral cats is far more difficult.

Fire certainly is something we can do something about. We can also do something about feral herbivores, such as feral cat or buffalo," he said.

"Cats are a much more bigger challenge and so are toads. Toads at the moment are only really implicated in perhaps declines of northern quoll."

A spokesman for Federal Environment Minister Peter Garrett says the problem is well known and the Government is acting.

The Government is funding work to reduce the damage of cane toads, tramp ants and camels.

It is also expanding the National Reserve System and coverage of Indigenous Protected Areas.

Both the Federal and Northern Territory Governments are also funding wildlife corridors.