A proposed 270 kilometre water pipeline to Broken Hill from the Murray River is not needed, scientists have said, because cheap and plentiful groundwater is available.

The $500 million project has been proposed by the New South Wales Government as the best way to solve the regional NSW city's water challenges.

But the councils at Broken Hill and Wentworth in western NSW, Mildura in north-west Victoria, and the South Australian Government are wary of the plan.

Concerns about water management in the Murray-Darling Basin have been in the spotlight again after ABC Four Corners reporting of the issue.

Sorry, this video has expired Who is benefitting from the billions spent on the Murray-Darling?

Hydrogeologists said they were convinced there was a large fresh groundwater resource in the Darling River floodplain, near Menindee in the NSW far west.

"The NSW Government says it wants to drought-proof Broken Hill, yet so far it appears to be ignoring the best available science," Professor Craig Simmons from the National Centre for Groundwater Research and Training said.

"With evidence-based and transparent decision-making, based on sound science and economics, and with careful management, these groundwater reserves can support outback communities such as Broken Hill."

Their argument involves the Talyawalka (formerly Jimargil) site near Menindee, which was the subject of a recent aquifer recharge study by Geoscience Australia.

Scientists think the groundwater could be pumped along a 27 kilometre pipeline to Menindee, then through an existing 114km pipeline to Broken Hill.

Dr Peter Dillon, from Adelaide's Flinders University and the International Association of Hydrogeologists, said the aquifer could be recharged when water was plentiful.

"It's a technique that's been known about for more than 20 years and that's starting to develop quite nicely in Australia," he said.

"We see stormwater being harvested and recharged into aquifers around Adelaide and also in Perth."

Aquifer option 'cheaper'

If the scientists are right, their solution could be considerably cheaper than a building a new pipeline between the Murray and Broken Hill.

"The proposed activity at Broken Hill would be a pipeline only one-tenth of that length, so it can make use of the existing water supply infrastructure and augment it with this resource," Dr Dillon said.

A staffer for NSW Regional Water Minister, Niall Blair, said a Murray pipeline would give Broken Hill long-term water security.

"The consideration of the various water supply options involved extensive economic, social, environmental and technical analysis to ensure that only options that were feasible were taken forward," she said.

"Due to the active River Murray to Broken Hill pipeline tender process, it would commercially disadvantage NSW taxpayers to release the details of the Broken Hill long-term water security business case."

Professor Simmons argues groundwater is becoming an increasingly vital resource in Australia.

"As our major rivers come under increasing pressure to provide adequate water for drinking, agriculture and the environment — particularly the Murray and Darling rivers — the use of groundwater will become ever more important," he said.

In May, WaterNSW shortlisted four contractors which want to build, operate and maintain a pipeline for the water utility.