Farmers are descending on Parliament House in Canberra to demand the Murray-Darling Basin Plan be scrapped.
The man responsible for implementing the plan acknowledges it is causing significant economic pain to some farmers around the basin.
But Phillip Glyde has described the impact as "immediate pain for long term gain".
Protesters say the plan has devastated regional communities, leaving them without schools, doctors and sporting teams.
The Convoy to Canberra group said there was water available but government policies were denying farmers access.
Mr Glyde said the plan would mean some farmers would have to leave their land but the industry as a whole would survive.
"I think the broader Australian community is unaware of the sacrifices that the farm community, the irrigators and agriculture community, is going through," he told ABC radio.
But Mr Glyde also pointed out it was the states that were responsible for allocating water.
Monday's protesters want the basin plan fixed or scrapped, more dam infrastructure and other measures like carp control to help improve conditions in the Murray-Darling.
Their convoy comes as the government progresses plans to provide subsidised water to farmers to grow fodder for livestock.
Federal Water Minister David Littleproud said on Sunday the first 40 gigalitres would be available for farmers from December 9.
Mr Littleproud also pointed out there was water sitting idle across the basin, calling on states to make sure farmers were using every drop they could.
Australian Associated Press