As river levels continued to rise last night and more rain is forecast, farmers in the Shannon basin were moving stock to higher ground and attempting to protect fodder threatened by the floods.
The hardest-hit areas were on the Shannon, south of Athlone, in Leitrim and along the River Suck valley in Galway and Roscommon, where waters have reached levels not seen since the late 1980s.
Farmers near Clonown, just outside of Athlone, have called on the Minister for the Environment, Mr Dempsey, to visit the area to see the damage caused and the difficulties created.
A spokesman for the Clonown residents said the flood levels there were the highest since 1954 and recent works carried out by the council to raise the level of the road had done little to help. He said there was an urgent need for remedial work on roads in the area.
There were similar complaints across the river in Carrickobrien, where again the water has risen to cover one of the roads leading into the district, but as yet none of the families living in the area have been cut off.
Mr Adrian Leddy, the Irish Farmers Association organiser in the area, said he feared the continuing rainfall would bring water levels to the same levels as in 1999, when many farms were cut off and fodder destroyed.
"There are tens of thousands of acres of farmland under water in and around Athlone and south into counties Offaly and Galway," he said.
He said there was very severe flooding north of Carrick-on-Shannon. "I have also had reports of severe flooding in Longford," he added.
He said there were fears along the River Suck, where local farmers had told him water levels were at an historical high.
There were reports last night of extensive flooding of farmland in the Gort area of Co Galway, in east Clare and in north Kerry and Co Limerick.