Fisheries officers are trying to save ailing Murray cod near Menindee, the location of several summer fish kills, by scooping them up in nets  and transporting them by road more than 100 kilometres downstream.

The move comes as water authorities stop flows in a weir to maintain the drinking water supply for Broken Hill.

The New South Wales Department of Primary Industries confirmed the plan on Thursday, as the town prepared for the arrival of Deputy Prime Minister Michael McCormack.

He is the most senior politician to go to the small township since significant numbers of Murray cod were discovered floating on the surface near Menindee in early January.

The deaths of the large deep-water dwelling fish became emblematic of the degradation of the Murray-Darling Basin.

Fish from another of January’s mass kills in the Darling. Photo: Facebook/Rod Mackenzie

Scientists believed they suffocated as an algal bloom died and sucked oxygen from the water.

The Murray-Darling Basin Authority had previously sought an expert opinion about a similar plan to relocate the Murray cod by hand, but decided it was too stressful for the fish.

However, the statement from the New South Wales department said it was now more lethal for them to remain.

“DPI Fisheries made the decision to proceed with this relocation due to the need for WaterNSW to cease flows from Weir 32 in the near future to maintain town water supply,” it said.

“This would leave the Murray cod even more susceptible to stress from low levels of dissolved oxygen.”

According to the plan, some fish would be moved downstream to the Lower Darling near Wentworth. The drive between Menindee and Wentworth is 240 kilometres.

They would be moved in a fish stocking truck that “is aerated and temperature monitored”.

Others would be taken to a fisheries centre “to regain health for future breeding and restocking purposes”.

According to the department’s website, Murray cod numbers have been dramatically reduced already in the Murray-Darling river system due to overfishing and environmental changes.

They can reach almost two metres in length and are predators that eat fish, crustaceans, water birds, frogs, turtles, mice and snakes.

The Greens are pushing for a federal royal commission into the handling of the basin and the fish deaths.

On Thursday, they released extensive terms of reference for that inquiry.

The party’s water spokeswoman, Sarah Hanson-Young, said the major parties must support the inquiry into a significant natural disaster.

But the government and Labor are yet to back a national probe.

-ABC