The risk of another mass fish kill in the Darling River over summer is very high as works begin to avoid a repeat of the environmental catastrophe.
The NSW government has begun rolling out a suite of measures following a damning report into the cause of millions of fish deaths at Menindee in March.
They include regular on-site monitoring, the installation of sensors and the establishment of an independent panel to advise on water-sharing plans.
Water Minister Rose Jackson on Friday said the measures formed part of the state government's response to the NSW chief scientist's review into the March event, which left an estimated 20 million fish dead.
The report, released in August, warned a repeat of the fish deaths at Menindee, in far-western NSW, was likely amid a drying climate.
Ms Jackson said the government was doing everything it could to reduce the risk of more major fish deaths.
"But with warm conditions and many fish in the Menindee weir pool continuing to put pressure on the system, the risk of more fish deaths over the coming weeks and months will remain very high," she said.
In his report, chief scientist Hugh Durrant-Whyte said many of the causes of the March fish kill had been well-documented but many previous recommendations had still not been implemented.
He said the lack of action represented a clear contributing factor to declines in the river system and fish deaths.
Professor Durrant-Whyte recommended the enforcement of environmental protections, urging the introduction of legally enforceable obligations and powers to ensure the health of the entire catchment's ecosystem was protected.
The federal government on Friday announced it was providing $2.3 million to develop a business case to look at how permanent fish passages could be built in Menindee.
The passages would ensure fish were able to travel through the weir rather than getting caught in deoxygenated water.
Environment Minister Tanya Plibersek acknowledged there were broader issues in the lower Darling River that needed system-wide intervention.
A revised Murray-Darling Basin Plan remains in legislative limbo as the government's focus on water buybacks comes under fire from the coalition.
"Measures like these fish ladders are important but alone won't help our native fish – we need to restore flows to let the rivers run," Ms Plibersek said.
The independent authority overseeing the basin's $13 billion management plan in July admitted there was no way it could hit legislated targets for water-restoring measures by June 2024.
In response, the Albanese government struck a new deal with NSW, South Australia, Queensland and the ACT to ensure water promised under the plan would be returned to the environment by the end of 2027.
