Two thirds of the land cleared was virgin bush, with most of the land clearing occuring in two states, New South Wales and Queensland on Australia's east coast.

"This means that over 50 football fields of Australian native trees, wildflowers and wildlife habitat are destroyed every hour," said the Australian Conservation Foundation.

The new land clearing figures are based on studies by the Queensland Herbarium, the New South Wales Royal Botanic Gardens and the New South Wales Parks and Wildlife Service.

In a joint statement green groups said the new studies were more accurate as they assessed the loss of trees and understorey plants like wildflowers and shrubs using satellite and aerial photographs and field observations. Previous estimates were based only on the loss of trees estimated by satellite images.

"Past estimates already rated Australia as the sixth highest land clearing nation on Earth," said Barry Traill, land clearing campaigner with the Wilderness Society.

"The new figures show that in fact we are the fifth worst land clearer in the world. We've overtaken Mexico and are fast catching up to Brazil, Indonesia, Zambia and Sudan," he said.

Green groups warned that the higher rate of land clearing threatened to make Australia's major salinity problem worse.