The first platypus was found tangled in a mesh trap by a bush regenerator working near the Jenolan River, while the second was found on the banks of the river after presumably suffering a similar fate.

"I noticed there was a bright yellow (string) like a tent rope tied to a tree so I went and had a look," bush regenerator Alan Oliver said.

"When I pulled it up there was a dead platypus in there.

"The real tragedy is we've never seen any yabbies in the Jenolan River."

The Jenolan River is home to a small number of platypuses that inhabit the larger pools, including the popular tourist attraction of Blue Lake.

But populations also live in creeks closer to Blue Mountains townships including Coxs River, Middle River, Bedford Creek, Glenbrook Creek and Erskine Creek.

"I think it would be hard to say exactly how well they (populations) are or aren't doing," Vickii Lett from the National Parks and Wildlife Service said.

"They are around and the important thing to think of, if you keep healthy creek lines and river systems, then they will continue to be around," she said.

Rubbish, trampling of creek beds, and clearing of vegetation can all jeopardise platypus populations.

However yabby traps are particularly dangerous because platypuses and other wildlife are attracted to the bait, get trapped inside or tangled in the mesh, and drown.

"It is not a good way to go," Vickii said.

Since November 2003 yabby traps have been banned in all public waters where platypuses are potentially found for just this reason.

This area covers most of eastern NSW and includes the Blue Mountains National Park.

However Fisheries NSW can give advice on modified traps which minimise harm to other wildlife and can be used west of the Newell Highway in central NSW.

Both Fisheries NSW and the National Parks and Wildlife have substantial fines for people endangering platypus populations by breaking this rule.

For further information contact Fisheries NSW on 1300 550 474 or the National Parks and Wildlife Service on 1300 361 967.