One of Australia's first crowd-funded scientific expeditions may have uncovered several new species of mammal in Papua New Guinea.

Euan Ritchie, an ecologist from Melbourne's Deakin University, raised $20,000 to document rare animals in the Torricelli mountain range in the remote north-west of PNG.

The money bought 40 camera traps and it was hoped these devices might capture the first images of critically endangered tree kangaroos in the wild.

But they have also snapped up to three new species of previously unidentified mammals.

"We certainly got an image of what we think is a new species of sort of small kangaroo, dorcopsulus wallaby. Think small dog-size wallaby if you like," Mr Ritchie said.

"There's also things like bandicoots and rodents that don't appear to be in any of the books that we know about.

"To actually confirm that of course we'll have to go back there one day and actually catch these animals and get them in the hand and take measurements and DNA samples, so that's for further down the track.

"But there's a whole range of species that are almost certain to be new to science and that are also new to that region."

Mr Ritchie says the discoveries show PNG has incredibly valuable forests and habitats and the region is a global biodiversity hotspot.

"There's a whole range, probably hundreds and hundreds of species, not just in mammals but the birds, the insects, all sorts of species that are probably unknown to western science," he said.

"We've really got to preserve those habitats because they're really valuable."

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Mr Ritchie partnered with the Conservation Alliance for the tree kangaroo project.

The director of the Tenkile Conservation Alliance, Jim Thomas, says tree kangaroos are the biggest native mammal in PNG so they are highly sought-after.

"In the remote areas, the bush is everyone's supermarket so previously people would go out and hunt the animals," he said.

"Because the tenkile and the weimang are big animals, they're the prize. So hunting pressure has caused a decline of these animals."

Mr Thomas and his wife Jean have spent more than a decade working with villagers to protect the tree kangaroos and their habitat through education, alternative food sources and water programs.

The endangered Tenkile tree kangaroo in Papua New Guinea captured on camera this year.

"Once people had tangible benefits in their villages and realised that we're here to help them," he said.

"That was the reminder not to kill these tree kangaroos, because they were hanging on by a thread when we first got in. The Tenkile was maybe at 100 animals."

Until recently, there has been little scientific proof of just how successful their work has been.

"For the two rarer species, which is the weimang and the tenkile tree kangaroos, we recorded the first camera trap images of the weimang ever," Mr Ritchie said.

"That's only the second time to my knowledge that the tenkile has been recorded. There's probably about five or six times as many giant pandas in the world as there is the tenkile tree kangaroo.

"So to get multiple images is really, really significant and really exciting for us because it's a demonstration, particularly for the Tenkile Conservation Alliance, that their work with communities, the local people, is actually having a positive effect.

"Tenkile numbers are probably actually increasing and so their long-term survival is looking quite good."

The Tenkile Conservation Alliance has about 50 villages signed up to its hunting moratorium.

Mr Thomas says the group is now working with the PNG government to legislate to have the area protected from logging and mining.