Authorities Investigate Latest New South Wales Fish Kill

Thousands of fish have died in another mass fish kill event in NSW, the state government says.

The fish, mostly juveniles between two and 10-centimetres in length, were found washed up on the banks of Lake Inverell on the Macintyre River on Monday, the primary industries department said in a statement on Tuesday.

Golden perch, Murray cod, eel-tailed catfish, carp, gudgeon and freshwater shrimp are among the species affected almost 900 kilometres from an earlier mass death event at Menindee.

The Darling River filled with rotting fish (Image AAP)

Fisheries officers are inspecting Lake Inverell amid reports larger fish have died upstream.

An estimated million fish died in the Darling River at Menindee in early January sparking a national debate over the use of Murray-Darling basin resources including allegations of water mismanagement.

But the government blames the drought.

"Much of NSW is currently experiencing heatwave conditions and the ongoing drought across western NSW has resulted in fish kills in a number of waterways recently," the department said on Tuesday.

"With these extreme conditions expected to continue over the coming months it is likely more fish kills will occur without significant rainfall to generate replenishment flows."

Menindee residents Dick Arnold and Rob McBride hold 'century-old' fish. Image: Facebook via Tolarno Station.

Water scientists have argued successive governments are at fault for allowing too much water to be extracted from the system for irrigation.

Water Minister David Littleproud launched a review on Tuesday, with the probe to look at why the fish died in multiple events and how future deaths can be avoided within the parameters of the Murray-Darling Basin Plan.

"It's important that we get an understanding of those fish kills," Littleproud told reporters in Toowoomba.

Professor Rob Vertessy will pick the other members of the panel looking into the mass fish deaths on the Darling River at Menindee in western NSW.

The Murray-Darling Basin Authority on Tuesday welcomed the independent assessment and said it will also prepare its own report for the minister containing recommendations.

Authority chief executive Phillip Glyde said more fish deaths are likely before the drought breaks, identifying the areas on high alert as the Lower Darling, Barwon-Darling, Namoi, Lower Murrumbidgee, Mannus Creek and Lake Inverell.

"At these and other sites, on advice from experts, governments are using aerators, releasing water where it is available, relocating fish to other habitats, and closely monitoring water quality including through satellite imagery," Glyde said in a statement.

Image: Rob Mackenzie (Facebook)

Over the weekend, the Australian Academy of Science agreed to Labor leader Bill Shorten's request for a three-week study into the Menindee fish kill, with the findings due before parliament returns.

Shorten welcomed the government's review but said he had written to the prime minister two weeks ago asking for an independent inquiry.

"They weren't interested then," he told reporters in Rockhampton.

"We publicly engaged with the Australian Academy of Science. The government again said they weren't interested. They finally got the memo."

He said he was happy for the government to be involved in Labor's review as the death of fish is "a national issue".

Rob Gregory posted footage of hundreds of dead fish to Facebook. Source: Facebook.

Vertessy researches climate change and water security at the University of Melbourne and chairs an independent committee which gives advice to the MDBA.

Before his current positions, he headed up the Bureau of Meteorology and held a senior role with CSIRO.

Littleproud said the first round of draft reports were due back by February 20 and final findings will be handed down in March.

"These fish kills were something that was predicated by one of the largest droughts we've ever seen in this nation's history," the minister said.

"We're having a fair dinkum independent panel have a good look at this - with proper access to the scientists and river managers who run the system."