Months of anticipation gave way to widespread disappointment when the NSW Office of Water announced a meagre 9 per cent allocation on Wednesday.

Above average rainfall and buoyant dam levels had raised hopes irrigators could get up to 30 per cent of their water in time to plan their summer cropping programs.

Debbie Buller from the Murrumbidgee Food and Fibre Association said there were "a lot of shocked and very disappointed" farmers following the announcement.

She said it appeared that dam levels had "very little to do with general security allocations" and called for an overhaul of how water was distributed.

"The problem is that if we can't have some type of secure access to water allocations in spring then it makes it impossible to for us to plan a farming program because that's when we need the water," Mrs Buller said.

"It's not very helpful to get water allocations after November if you're going to plan a summer cropping program because it's too late.

"It's not as if we can suddenly jump on our tractors and plough our ground and put on our fertiliser and sow our seed overnight.

"Under the present system, where we've got no secure access to the water, we can't farm - it's all guesswork."

The disappointment was eased slightly when Murrumbidgee Irrigation announced it would provide its customers with 14 per cent of their water - 5 per cent above the allocated amount.

"Our announcement has been made in line with company policy on sharing water savings," MI's managing director Brett Tucker said.

"It is a critical time for customers considering growing summer crops and today's announcement will assist with those business decisions."

NSW water commissioner David Harriss stated he was "very mindful" it was a critical time of year for general security irrigators and said allocations would be reassessed on September 15.