The NSW Greens have called for a royal commission into the management of the Murray-Darling Basin, as clean-up begins in outback NSW after the biggest fish kill in the region's history.
Millions of dead fish have washed up on the Darling-Baaka River at Menindee and towards Pooncarie, near the borders of Victoria and South Australia, after prolonged flooding and repeated heatwaves in recent weeks.
Authorities estimate up to 20 million fish have died due to low levels of dissolved oxygen in the water, known as hypoxic blackwater, which was exacerbated by the weather extremes.
The kills are thought to be worse than another mass fish death in early 2019 during a severe drought, when one million washed up dead.
NSW Greens MP Cate Faehrmann, who visited Menindee this week, called for a royal commission to investigate management of the Murray-Darling Basin, including environmental flows and irrigators' allotments.
The commission should look at the role of government departments and whether water policies adequately address climate change, she said.
"Climate change is making droughts more severe and frequent, and reducing inflows into our rivers," Ms Faehrmann said in a statement on Wednesday.
"The NSW government has left the basin completely unprepared for the realities of the climate crisis."
About 50 Menindee residents attended a meeting with emergency services on Tuesday, while others said they were too frustrated to go and were skeptical about water management after the 2019 kills.
Federal Environment and Water Minister Tanya Plibersek said the fish kill was devastating for Menindee and the environment.
Ms Plibersek said the federal government was working with the states under the Murray-Darling Basin Plan to ensure adequate water for agriculture, the environment and communities.
"We will deliver on the Murray-Darling plan in full," she told parliament on Wednesday.
South Australian authorities were monitoring river conditions as water from NSW will flow across the border next week.
SA Environment and Water Minister Susan Close said the risk of a major incident was unlikely, as the flows will mix with water from the Murray which has higher oxygen levels.
An Emergency Operations Centre was set up in Menindee on Sunday to prioritise the protection of the town's drinking water.
NSW Police Assistant Commissioner Brett Greentree said initial clean up efforts have begun, but it would take some time after the deaths of up to 20 million fish.
"It's an unprecedented scale now and a logistical nightmare," Mr Greentree told ABC's RN Breakfast.
Specialist contractors have been called in to help, while Fire and Rescue NSW officers were using booms to move the animals to shore for disposal.
"In reality, in terms of cleaning them all up, I would I would think that would be very, very challenging and I doubt that would happen," Mr Greentree said.
Another community meeting is due to be held in Menindee on Friday.
