Sydney  - The Murray-Darling river basin where one-third of Australia's food is grown is in dire straits because upstream farmers are taking too much water for irrigation, scientists warned Wednesday.

They said parts of the basin would be "beyond the point of recovery" unless the government bought back water allocations and got more water flowing by October.

"There has been 10 years at least where people have said you have got to restore the environmental flows to the system if you want to keep the natural assets," Adelaide University's David Paton told national broadcaster ABC.

"We've failed to do that. Now we should be seriously trying to repair the damage and at least prevent it going to the point where, when we do have water back, which might be two or three years away, you're just not going to have a system which you can recover," he said.

Australia, recovering from its worst drought in a generation, has high hopes that rains in the winter and spring will help rescue the Murray-Darling.

The scientists leaked their report to the press because the government that took delivery of it in May said it would not respond until the end of the year.

Greens leader Bob Brown said the government's inaction was outrageous. He said ministers "have put this report on the shelf when the scientists are saying there was urgent action required and if you wait that long, it'll be too late." (dpa)