Residents are angry about a $24 million deal to help the Darling River flow again.

The NSW Government is working on a plan to divert water from the Warrego River to the western floodplain, a diverse habitat for birds, fish and frogs.

Member for Barwon Roy Butler has labelled the plan “illegal”.

“That water would make all the difference to a town further downstream, to having their weir pools replenished or having the holes in the river filled for fish habitat,” Mr Butler said.

The plans include the installation of automated regulator gates to allow the national park's staff to control river flow.

Mr Butler said the plan could be illegal, because the government does not have the infrastructure to measure the water leaving the river system.

“If any normal person put in place an illegal diversion on a river or a creek, they would be taken to court but here we have government putting in place an illegal diversion onto a flood plain,” Mr Butler said.

The NSW Government says the amount of water diverted onto Toorale's western floodplain will be calculated based on figures from existing upstream gauges combined with the proposed new dam discharge gates.

The government says this will see more water would going down the Darling River, and more water being directed to the Darling River in drier years.

Its spokesperson has told reporters that any work on Toorale, and the subsequent operation of any works, will be done in accordance with all legal instruments.

“Irrespective of who owns or operates the works, the Natural Resource Access Regulator is there to make sure all works are built and operated legally,” the spokesperson said.