A proposed management plan to save the Murray-Darling Basin after decades of degradation has finally become a decree on Thursday, with Federal Environment Minister Tony Burke affixing his signature to make the plan a final legality.

"The Murray-Darling Basin Plan is now law," Mr Burke tweeted.

But the plan, which targets to bring back 2750 gigalitres of surface water annually to the environment, to the environmentalists, remain a shallow one.

The plan will not return the health and once pristine condition of the river, Conservation Council SA said.

"The adjustment bill passed by the Senate on November 22 is still based around a reduction of take of 2,750GL ... this falls far short of what the system needs", Tim Kelly, Conservation Council SA chief executive, said in a statement.

"The proposed 'Special Account' to increase this to 3200GL also falls short of what the system needs, plus there is no legal requirement for the 'Special Account' to result in the promised 450GL of extra water," he added.

Admitting the management plan was a hundred years late, Mr Burke hoped it would still not be too late to save the Murray-Darling Basin.

''Today, under the Gillard government, Australia, a century late, but hopefully just in time, has its first Murray-Darling Basin plan," Mr Burke said at the Press Club in Canberra.

''Today is the day Australia decided to restore the Murray-Darling to health.''

The plan will entail recouping 2750 billion litres of water from farmers and irrigators for the environment by 2019, where $10 billion will be spent to produce this vision based on efficient irrigation infrastructure, pumping and piping projects on wetlands and floodplains, and buy backs of water entitlements from farmers.

The government, by 2024, will also spend another $1.8 billion to try to recover an additional 450 billion litres for the river.

But Kelly O'Shanassy, Environment Victoria chief executive, said the Basin Plan does not return enough water to rivers to protect their environmental values in the long term.

"It returns only enough water to meet a little over half of the environmental objectives set for the river system," she said in a statement.

"It was our big chance to provide a sustainable future for the rivers and their communities and the plan presented by Minister Burke today fails this basic test."

The final plan is available online at www.mdba.gov.au.