A new scientific report warns parts of the lower Murray River may be beyond recovery without water by October.

But the Rudd government has deferred consideration of the report until a meeting of the Murray-Darling Ministerial Council in November.

The report, prepared by a scientific panel and leaked to the ABC, warns there are six months to save crucial parts of the Murray-Darling Basin.

Without sufficient water, ecosystem recovery may take years to decades and the unique ecology of the lower Murray will be irreversibly lost, it says.

Vegetation on the lower Murray had been lost and wetlands were dry while some fish species might already be extinct.

Dr Arlene Buchan, healthy rivers campaigner for the Australian Conservation Foundation, said that waiting until November could be detrimental to the system.

"You don't often hear a scientist using language of this strength," she told ABC Radio today.

"They're being crystal clear about the need for water, the short period of time, the urgency of the problem and the consequences of not acting.

"What the ministerial council have done is ignore the urgency that is portrayed by these scientists.

"They have more or less made a decision about the lower lakes and the Coorong by not making a decision to return water to them."

University of Adelaide ecologist Associate Professor David Paton said some fresh water lakes were on the verge of bring unrecognisable.

"As far as I am concerned there has been 10 years at least that people have said you have got to restore the environmental flows to the system if you wish to keep the natural assets," he told ABC Radio.

"We have 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 are just not going to have a system that you can recover."

There were suggestions coming from some in South Australia that Lake Albert may never be freshwater again.

"The writing is on the wall," Prof Paton said.

"Lakes Albert and Alexandrina and even the Coorong might be very different systems to what they have been throughout the 20th century."

Governments will act: Wong

Water Minister Penny Wong said governments were seeking advice on what should be done to save the basin and could take action before the ministerial meeting.

Advice was being sought on the best way to save the lower lakes of the Murray, which scientists say are fast approaching an ecological catastrophe, she said.

Senator Wong says the federal government appreciated the urgency of the situation and was looking for solutions. "We know this is an urgent problem," she told reporters.

"I have asked for urgent advice on what we can do in the short term."

Ms Wong rejected criticism that federal and state governments were acting too slowly to combat the crisis in the drought-ravaged basin.

 "There's been no deferral on dealing with the lower lakes and Coroong," she said.

Senator Wong acknowledged she had received the scientific report and said that, in response, $6 million had been allocated to pump water between South Australia's lower lakes as a short-term aid.

Senator Wong said she would consider getting water ministers together before the November meeting if necessary. "If urgent decisions need to be made by the ministerial council, that can occur out of session," she said.

The federal government's $3.1 billion water buy-back was the best way of relieving pressure on the Murray-Darling, Senator Wong said, as she reiterated that all buy-backs would be voluntary.