The Turnbull government has backed a plan to cut the amount of water set aside for the environment, and redirect 70 gigalitres to agriculture because of concerns about job losses in rural towns.

Murray-Darling Basin Authority chief executive Phillip Glyde said the changes, including a proposal to reduce the water recovery from agriculture in the Northern Basin from 390 gigalitres to 320 gigalitres, struck a "sensible balance between social, economic and environmental interests."

Mr Glyde said the reduction would save about 200 jobs in irrigation-dependent communities while continuing to deliver about the same level of environmental outcomes.

"We need to be smart about how we use the 320 gigalitres of water if we're going to improve the health of the northern rivers. That's why our recommendation is contingent on the Australian, New South Wales and Queensland governments committing to a range of measures that aren't directly linked to water recovery," he said.