"I commend the government for taking this opportunity to buy water entitlements back for the environment but it should be noted that the vast majority of this water will help the Darling River system, not the Murray River system," Senator Xenophon said.

"The two major water buybacks by the federal government have been in New South Wales. And the reason we haven't seen similar buybacks in Victoria is because of that state government's four percent cap on trading water out of their region."

"If we are going to save South Australia's Lower Lakes and the Coorong, we need the Federal Government to make similar purchases in Victoria.

"That can't happen with the Victorian government calling the shots.

"This is further proof of the need for a national take-over of the Murray-Darling.

"We need one river system with one set of rules."

Senator Xenophon also emphasises that the water purchased was general security and supplementary security water.

"A lot of this water will only exist in wet years," he said. "Last year, allocations for supplementary security water in the Murrumbidgee was at 0pc and general security averaged around 20pc.

"This is a good start, but we need Basin-wide buybacks, not simply buy-backs that overwhelmingly benefit the northern basin."