A study has found that more than 40 per cent of Australia remains undamaged by humans.

Scientists from the Pew environment group and the Nature Conservancy have identified Australia alongside Antarctica and the Amazon as one of the five most important wild areas on earth.

But the study also found Australia has the world's highest rate of species extinction because of threats from feral animals, invasive weeds and bushfires.

Report author, Dr Barry Traill, is concerned that only 10 per cent of Australia's wilderness is protected.

He says the number of Indigenous rangers should be increased from 700 to 5,000 to help conserve the environment.

"Areas such as the north Kimberley coast are owned by Aboriginal people and many of them are doing excellent work managing that country, providing environmental services for all Australians," he said.

"But we think more assistance would be invaluable in doing the works required to make sure that country stays in absolute top condition."