An environmental professor argues the Murray-Darling Basin Plan has failed and needs to be overhauled after a mass fish death event in the Darling River system.
Water management in Australia's third-longest river must be completely reformed, a leading environmental professor says, as the blame game over a mass fish death event in far western NSW intensifies.
Up to a million fish died in the Darling River system this week.
Residents are pointing the finger at state and federal governments for draining too much water from the Menindee Lakes and over-allocating the precious resource to irrigators.
But the peak body for Australian irrigators - the National Irrigators' Council - has hit back insisting farmers on the river's north have received no allocation of water in the past 12 months.
Scientists argue mismanagement of the river system is to blame although the NSW government insists the ongoing drought is a key factor.
Australian National University honorary professor John Williams says the current Murray-Darling Basin Plan has failed and needs to be overhauled.
"The real problem is managing the Darling under this plan has been far from satisfactory," Prof Williams told AAP on Friday.
"It's taking too much water. We need to have substantive change."
The scientist claims the plan allows too much extraction at the northern head of the river and doesn't factor in how to manage the system in drought.
Prof Williams admits it's difficult to manage but warns there'll be more fish deaths if there isn't a 30 to 40 per cent reduction in the amount of water extracted.
A South Australian royal commission in 2018 investigated allegations of water theft from the Murray-Darling Basin by rogue irrigators with a report due in February.
Senior counsel assisting the commission, Richard Beasley, told AAP in a statement on Friday that the mass fish deaths are "terrible" and some of the issues raised fall within the commissioner's terms of reference.
Only the commissioner can request additional time to consider the event but Mr Beasley on Twitter said it would be the "right thing to do".
NSW opposition leader Michael Daley has called for a special commission of inquiry into the incident and vowed to establish one if Labor wins power at the March election.
NSW Primary Industries Minister Niall Blair - who has been savaged by some Menindee locals for partly blaming the drought - said in a statement that fish kills are not a new phenomenon and happened in the region between 2002 and 2004 during the millennium drought.
He's requested an urgent report.