A new study by the Australian National University claimed the Murray-Darling basin could be missing billions of litres of water.

The authors have claimed the Federal Government have overstated the amount of water being returned via water savings, but the government has rejected the report’s findings and are standing by their figures.

Co-author Professor Quentin Grafton said, “ You’ve got a Murray-Darling Basin Authority making claims that there's all this increase in stream flows yet they actually haven't done the work that's necessary to work to find that out.”