THE Murray-Darling Basin Authority has failed to plug a 971-gigalitre hole in its draft plan to divert 2750GL of water to the environment.

Southern NSW, Victorian and South Australian irrigators will have to contribute 1389GL to water wetlands in their own valleys, plus another 971GL to boost the "downstream needs" of the Murray mouth and Lower Lakes.

  But in its draft plan released on Monday, the MDBA failed to mention how or who would deliver this massive 971GL flush down the Murray River.

Irrigation industry leaders claim MDBA boss Craig Knowles deliberately avoided the contentious issue, leaving the states and Federal Government to bicker over the carve-up.

Victorian Farmers Federation water council chairman Richard Anderson said the MDBA draft had created more uncertainty than the guide released last year.

"If you compare it to the guide, this is worse," Mr Anderson said.

National Irrigators Council chairman Stewart Ellis said Mr Knowles' failure to divvy up the 971GL was a deliberate ploy.

"I think he just wants to leave it to the states," Mr Ellis said.

The issue sparked anger last year when Murrumbidgee irrigators discovered they were expected to contribute 205-235GL towards downstream needs, while Victoria's Goulburn-Broken irrigators only had to contribute 91-93GL.

But the MDBA's decision to leave the 971GL in limbo has raised fears among Victorian irrigators they will be hit hard in any interstate dispute.

A similar dispute, over the recovery of 500GL under the Living Murray Initiative, led the governments to agree on sharing the burden, based on how much they each diverted from the basin's rivers.

But applying the same diversion rule to the 971GL would force Goulburn irrigators to deliver an extra 193GL to meet the basin's downstream needs, compared to 93GL under the guide.

Victoria's Murray irrigators would also be worse off under the diversion rule, contributing 203GL to meet the basin's downstream needs.

Mr Anderson said the best way to deal with the issue was to remove the 971GL from the plan, cutting the 2750GL target to 1779GL.

The MDBA has already flagged reviewing the plan in 2015 to assess infrastructure projects aimed at boosting the efficiency of environmental watering.

Victorian Water Minister Peter Walsh agreed the 971GL should be quarantined and found through environmental works and measures.

But Federal Water Minister Tony Burke said the MDBA had got the balance right and the draft would now be subject to 20 weeks of consultation in the lead-up to finalising the plan.