There has been no overall improvement in the health of Australia's biggest river system after five years of the Murray-Darling Basin Plan (MDBP), scientists say.

Key points: The MDBP governs the use of water from Australia's largest river system

The MDBP governs the use of water from Australia's largest river system A new report says the amount of water allocated for environmental flow needs an increase by one third to improve river health

A new report says the amount of water allocated for environmental flow needs an increase by one third to improve river health Report also recommends $600m from plan be allocated to help struggling rural communities

"Without substantial changes, the MDBP will fail," warns a report due out today from the Wentworth Group of Concerned Scientists.

"Scientists like myself have a responsibility to provide politicians with advice on what a certain volume of water will and won't do," lead author Jamie Pittock told AM.

"The sort of volumes of water that are [currently] available won't deliver the conservation of some of those key environmental assets they said the plan was about."

The MDBP is a historic, bipartisan agreement about how to use the water that flows down the river system.

A map of the Murray-Darling Basin in Australia. ( ABC News: Ben Spraggon )

The report calls on state and federal governments who jointly manage the MDBP to commit to a one-third increase in current environmental flows to 3,200 gigalitres.

The MDBP targets a minimum 2,750 gigalitres, with another 450 gigalitres on top of that dependent on proof that there would be no adverse socio-economic impact on rural communities.

A new socio-economic survey of the basin, due to report to state and federal water ministers by December, will be key in deciding on a permanent environmental target.

$600m needed for struggling communities: report

Previous surveys have found a negative socio-economic impact in several rural communities, for example Collarenebri in Northern New South Wales and Deniliquin in the state's south.

Today's report will call on $600 million from the plan to be devoted to economic transition programs for struggling communities.

"The Government, the Australian society, that's taken the decision to change the way the basin operates, has a moral obligation to invest in those communities," Dr Pittock said.

He questioned the impartiality of the latest COAG survey.

"We would like to see some improvements to make it more independent," he said.

"We're very concerned about the lack of adequate monitoring of the basin plan implementation.

"We are concerned that a number of political leaders are trying to frustrate the acquisition of that extra 450 gigalitres.

"We are certainly concerned that the New South Wales and Victorian governments are not implementing the plan in the constructive way that we would hope."

This week AM will be broadcast live from communities along the Murray-Darling Basin, assessing its impact five years after its introduction.