Murray MP Helen Dalton weighed in on the findings by saying the tragedy could have been avoided with better water management.

"Griffith mayor John Dal Broi has cherry picked the report in a desperate attempt to avoid responsibility for the demise of a lake his council is supposed to manage," Ms Dalton said.

"The report clearly identifies very poor water quality as a contributing factor, but Dal Broi doesn't mention this in his media release."

The Department of Primary Industries Fisheries stated there was insufficient evidence to determine a single, specific cause.

"Back in 2017, Dal Broi rejected Geoff Sainty's plan to improve the lake's water quality, he's one of Australia's leading wetland specialists," Ms Dalton explained.

"I believe this once-in-a-generation tragedy could have been avoided if Dal Broi accepted expert advice to fix this lake three years ago."

The mass fish kill that occurred on May 23 and 24 saw thousands of species of dead native fish wash up on the shores of Lake Wyangan.

It was likened to that of the Menindee fish kill last year by the Murray MP.

"Dal Broi has been mayor of Griffith on and off for 30 years," Ms Dalton said.

"Under his watch, the lake has gone from the heartbeat of the town to a toxic cesspool."

Mayor John Dal Broi dismissed the accusations made by MP Dalton, instead welcoming the findings of the report.

"What the report does say is what was not the cause," Mr Dal Broi said.

"There are people out there suggesting that it was mismanagement, but the report certainly dismisses that."

Helen Dalton refused to acknowledge the comments made by Dal Broi, and asked him to take responsibility.

"Dal Broi needs to apologise for sourcing the town's drinking water from the toxic lake in 2017, without warning residents beforehand," Ms Dalton added.

"The buck stops with the mayor, he needs to man up, stop blaming others and fix this lake."

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