Shadow Minister for Water and Cessnock MP Clayton Barr has accused the Nationals representative of not thinking the project through.

Mr Johnsen recently revealed that he had requested to state Minister for Water, Melinda Pavey, for the piece of water infrastructure to be a priority.

Designed to hold 450 gigalitre, it would be located near the 1335 hectare Camerons Gorge Nature Reserve between Murrurundi and Scone, on the Pages River.

A recent costing by the 20-Year Infrastructure Options Study put the project at almost $900 million, meaning it would likely require federal funding, as admitted by the Parliamentary Secretary for the Agriculture.

While the opposition has criticised his handling of the current water crisis and stated that putting a dam in a river that is not flowing is an ill-conceived idea, he had a different perspective on the topic, describing it as a future-proofing effort.

"A dam would naturally both service the Upper Hunter and Lower Hunter regions and help in any future dry conditions," he said.

"I think a new dam would meet community expectations and provide for our local communities and farming industries."

However, Mr Barr has said it would cause more harm than good and heavily hit the pocket of locals.

"Building a dam like this will have a massive impact on farmers and water users downstream, who need to be carefully consulted before this thought bubble progresses," he said.

"Hopefully, the local MP Michael Johnsen has explained to his community that they could pay two, three, four or even five times as much for their water if a dam like this were built."

Another one of Labor's main queries was as to why the news that this project was being seriously considered has only materialised in the past week, essentially accusing him of jumping on the bandwagon.

Once again, he rebuffed those claims, revealing that he had been in conversations over the proposal since NSW's water strategy document was published in June, 2018.

Although he did divulge that he thought now was an appropriate time to really push the issue.

"On behalf of my constituents, I think it is important to be part of the debate," he said.

"I think there is a much greater appreciation of the need to have secure water storages than there has been in the past."