Federal Environment Minister Peter Garrett announced this morning that a South Australian proposal to flood Lake Alexandrina with salt water from the Coorong would be subject to an Environmental Impact Statement.

Ms Hanson-Young said the announcement was yet another deferral in a long running saga, which was devastating people living in the Lower Lakes region.

"Yes, an environmental impact statement is the action that was needed, but blind Freddy could have seen that," she told AAP.

"What we need from our environment minister is a commitment to maintaining the health of the lakes and to uphold his duty of care in the long term.

"His announcement is simply another nail in the coffin for the Lower Lakes."

Ms Hanson-Young said she believed the IAS should be conducted by an independent commission, and not the Rann Government.

"I think the State Government has put its cards on the table quite clearly as long back as the middle of last year saying that this was the option they were considering and it seems that the Federal Government seems to be a little obsessed with the idea as well, instead of putting their energies and their focus on to the main game of securing fresh water," she said.

"The State Government's response to what's been going on in the Lower Lakes has been pitiful to say the least around praying for rain."

South Australian Premier Mike Rann said that any decision to flood the Lower Lakes with salt water was a "last resort" and would be delayed to allow for potential good inflows provided by Winter and Spring rains.

It was the State Government that sought approval from Mr Garrett to flood the Lakes with salt water to prevent acidification, but was instead ordered to conduct a more extensive environmental assessment.

"The last thing the Government wants to do is flood the lower lakes with sea water," Mr Rann said in a statement released today following Mr Garrett's announcement.

Ms Hanson-Young said the reason the Lower Lakes are now in such a dire situation was because too much water had been taken out of the system.

"We need to be putting aside an allocation (from up-stream) specifically for the environment," she said.