IRRIGATORS have warned they will fight the Federal Government's "unfair" claw back of water for the environment under the new Murray Darling Basin cap.

Victorian and NSW irrigators have condemned the Federal Government and Murray Darling Basin Authority's rushed drafting of the plan, with government bureaucrats from both states warning it was a "train wreck".

Under the draft plan, the Federal Government will establish new sustainable diversion limits cutting the volume of water available to the basin's two million inhabitants.

The limits will not be invoked until 2014 in NSW and 2019 in Victoria.

But irrigation industry leaders warn the impact of the Government's rush to issue draft SDLs by June this year will echo through the basin community for decades to come.

The MDBA released an issues paper on the SDL process in November, then demanded the community lodge submissions by December 18.

Victorian Farmers Federation water council chairman Richard Anderson said irrigation communities could not afford to be complacent on the issue.

"If we do nothing we may end up with nothing," Mr Anderson said.

Residents of basin towns from Bendigo to Bourke in NSW, irrigators and stock and domestic users will have their access to water cut so the Federal Government can create "environmentally sustainable levels of take".

Irrigation industry leaders say they have been stunned to learn the Government will not share the pain of the cuts fairly across the basin.

The Murray Darling Basin Authority will instead claw back water based on the gap between what the Federal Government has already recovered, under its $3.1 billion water purchasing program, and what is still needed within each catchment for the environment.

National and state farmer groups attending MDBA briefings on how the new SDLs would be calculated said they were amazed the Government could implement such an unfair system.

"You'll face big cuts to your reliability or entitlement if the Government hasn't already bought enough water in your system to meet the SDL," Victorian Farmers Federation water council chairman Richard Anderson said.

An MDBA fact sheet on the SDL process backs up irrigators' fears.

Victorian irrigators face substantial cuts given the Federal Government has only bought 136,000 megalitres of the state's 2.2 million megalitres of high-reliability water shares.

The SDL process is also likely to force cuts in Bendigo, Ballarat and even Melbourne's Goulburn-system entitlements.

In NSW, Namoi Water executive officer John Clements said the SDL process was unfair and flawed, given the Government had bought less than 6000 megalitres in his valley, compared to nearby Gwydir Valley irrigation system where it bought 74,000 megalitres.

"We will get out and create real havoc over this in February," Mr Clements said.

"We've raised this with (Federal Water Minister Penny) Wong, but she just shrugs her shoulders and says it's an issue for the MDBA (Murray Darling Basin Authority)."

Yet the whole process is being driven by Senator Wong's department, who requires the MDBA to implement the new cap as specified in the Federal Government's Water Act 2007.

"I think she (Wong) hasn't bothered getting around the detail of this because she knows the politics of it," Mr Clements said.

Mr Clements and Mr Anderson said they expected Senator Wong to blame the states if irrigators and their state governments rejected the SDL process.

Irrigators still don't know whether they will receive any compensation.

"We still don't know what's happening with the risk assignment," Mr Anderson said.

A MDBA spokesman said the short time frame for submissions on the SDL process "reflects the overall timeframe the authority is working to in order for a proposed Basin Plan to be released in mid-2010".

Meanwhile, managers from the Victorian Department of Sustainability and Environment, water corporations and catchment management authorities say they're appalled at the MDBA's rush to get the draft SDLs out by June and the paucity of detail on how the environment's "take" would be figured. Key concerns are:

The SDL paper only gives "lip service" to the social and economic impacts of cutting communities' water access.

No detail on what environmental assets (eg. floodplain forests, wetlands or lakes) the Government wants to revive.

No detail on how much water the MDBA wants to recover to water the environmental assets.

No detail on how the impacts of climate change will be factored into the SDL.

No detail on how much water Murrumbidgee and Goulburn irrigation communities will have to contribute to reviving downstream Murray River assets such as South Australia's Chowilla floodplain, Lower Lakes or Coorong.

The MDBA spokesman said the authority was developing an environmental watering plan and would consider social and economic consequences. Senator Wong's office did not comment.