One in five species of Australian mammals are at risk of extinction, a new report revealed on Tuesday.

Of the 388 species of mammals found naturally in Australia, 78 are listed as vulnerable, endangered or extinct in the wild.

In addition, nearly 14 percent of amphibians, five percent of reptiles and six percent of birds are at risk.

The figures are included in a new report, The Numbers of Living Species in Australia and the World, released by Australian Federal Environment Minister Peter Garrett.

Garrett said the report was the only one in the world to document the world's 1,899,587 known plant and animal species.

The report also found 93 percent of Australian reptiles and 87 percent of Australian mammals were unique to the island continent.

In the three years since the last report was tabled, scientists have identified an additional 48 reptiles, eight frogs, eight mammals, 1,184 flowering plants and 904 spiders, mites and scorpions.

However, the 147,579 Australian species identified by the report were believed to account for just 25 percent of the total number in existence, Garrett said.