A call from 12 prominent scientists and economists for radical change to the Murray-Darling Basin Plan has been rejected by the basin authority.
The group signed a declaration in Adelaide on Monday saying that billions of dollars spent so far had failed to achieve better water flows.
"This is not about politics or about playing the blame game," Australian National University economics professor Quentin Grafton said.
"It is about saying water reform is not delivering what it said it would for the basin, its environment or its people and saying how we solve it."
Professor Grafton said $4 billion had been spent on subsidies for irrigation infrastructure by governments over the past decade without any adequate measures of what had been achieved.
The group called for a halt to all public subsidies and grants towards infrastructure projects and for an independent audit to examine environmental outcomes.
But Murray-Darling Basin Authority Chief Executive Phillip Glyde said he was greatly concerned with calls to halt implementation of the plan.
Mr Glyde said it was a visionary long-term policy with water infrastructure efficiency programs already saving 700 gigalitres for the environment.
"Claims that the plan's investment in more modern and efficient water infrastructure is not delivering benefits for the environment are simply not true," Mr Glyde said in a statement.
"It is simply not possible to repair 100 years of damage to such a vast river system overnight or even within five years."
The basin plan was signed in 2012 and governs water use across the nation's biggest river system.