Murray-Darling authority acted unlawfully

Australia's Murray-Darling Basin Authority acted unlawfully and water allocations must undergo a complete overhaul across the system, a royal commission has found.

The commission's report released today found river allotments were driven by politics and accused the basin authority board of maladministration over its disregard for science.

It said water levels must be made on a scientific basis and in accordance with reconstructed water laws.

It also wants uniform penalties between basin states for irrigators who don't comply with regulations.

The South Australia-based royal commission's 736-page final report includes 111 findings and 44 recommendations aimed at improving the effectiveness of the Murray-Darling Basin Plan.

It says the Murray-Darling Basin Authority acted unlawfully when it "completely ignored" climate change projections for the determination of water allocations.

"The (sustainable diversion limit) ignores the best available scientific knowledge," it says.

"As an administrative decision, it is indefensible."

South Australian Premier Steven Marshall said the commission had strayed from its initial aim.

“I will not respond to the individual findings today because I think it is fair enough that we provide a copy of this to every other jurisdiction, we seek input from every other department and cabinet ministers and respond accordingly,” Mr Marshall told reporters.

“There are many allegations and recommendations in here, some of them are tough, we will look at every one of them and respond accordingly.”

The findings come as more than one million fish have been killed and entire towns are struggling for drinking water amid the ongoing drought crisis hitting NSW.

Despite the Menindee Lakes being vital breeding grounds for fish, feeding into the Darling River for 25, 000 years, the state government has declared it will permanently reduce the size of the lakes to build a water pipeline for Broken Hill.

That decision has sparked a political uproar among politicians and local residents - particularly because NSW Nationals Leader John Barilaro has been refusing requests to travel to Menindee to speak to the people.