Illegal poachers of dugongs and turtles in northern Australia now face fines up to 750,000 US dollars as the federal government shores up its protection of endangered species.

New laws were passed by the Senate late Thursday night to increase the fines for hunting in Commonwealth waters.

Environment Minister Greg Hunt told the Australian Broadcasting Corporation (ABC) that it was an important legislation.

"I am determined to wipe out any residual practice of poaching of dugongs and turtles," he said. "I think what we find is that these are majestic creatures."

Traditional land owners hope the increase in fines will deter poachers while ensuring native title holders can continue to hunt for personal, domestic or non-commercial purposes.

"We do have a lot of people who are taking those kinds of marine resources," Gavin Singleton, from the Dawul Wuru Indigenous Corporation near Cairns, told the ABC. "It's unsustainable."

Dugongs, the only strictly marine herbivorous mammals in the world, are among many Australian species under threat, with a recently released study stating 21 percent of Australian mammals are threatened with extinction.

The situation for threatened mammals was "catastrophic," according to the study's co-author John Woinarski, a conservation professor at Charles Darwin University.

The federal government has increased its conservation budget by an extra 560,000 US dollars and boosted 11 research and protection projects across the country.

Environment Minister Hunt said a similar project had been crucial to the survival of the eastern bettong, a rat-kangaroo wiped out on the mainland in the 1920s by rabbits and foxes.

"It's being reintroduced into the mainland. There are real things happening that are making a big difference," he said.

Woinarski said more needed to be done faster.

"The extent of the problem is huge and the extent of resources committed to it is nowhere near sufficient at this stage," he told ABC.