Thousands of farmers could be seriously disrupted or even forced out of business because of plans to build a pipeline to channel water from the lower Shannon to Dublin, it has been claimed.
The farms are located along a belt of land which has been earmarked for the pipe line on the Eastern and Midlands Water Project.
It is expected to be up to six months before the final route selection is clarified.
Between 1,000 and 1,250 farmers could have their worst fears confirmed when the route selection is announced later this year.
Hundreds of concerned land owners voiced their serious concerns at meetings in counties Kildare, Offaly, Tipperary and Clare over the past week, when many land owners first became aware that their holdings are under consideration for the pipe line.
The outline timetable for the project is that the Environmental Impact Assessment should be completed by late Summer 2016. The planning application to Bord Pleanala is scheduled for the third quarter of 2017 and the oral hearings on the application are scheduled for mid 2018. If approved, the project would be constructed between 2018 and 2022.
IFA environment chairman, Harold Kingston described the planned pipeline as being "of serious concern to farmers because of the major disruption it is going to cause to farming" during construction.
He said that the two-metre wide pipe will require permanent way-leave rights being registered on the land by Ervia.
While the land will return to normal use for most types of farming when construction is completed, there will be some permanent restrictions on land use for development and, in particular, forestry.
One of the big issues with the reinstatement of the land is drainage, he said, describing drainage experiences on some previous schemes as "quite outrageous".
He said that sites will also be acquired for a number of pumping stations. The pipe line is planned to serve several major towns across the country.
Farmers attending the meetings threatened to oppose the development "all the way" when it comes to planning stage .
Some insisted that the extraction of sea water close to Dublin should be pursued as an alternative.
"My farm has been cut in two by a motorway and if this project goes ahead the land will be cut in four. It will be worthless", one farmer declared.
"I will be out of milking cows for years. I can't settle for compensation. I will oppose planning for the scheme because it will put me out of business," he added.
Many farmers said that the first they knew that their farms were on the route was when officials came to walk the land. There were calls for "unity to keep officials out" until the situation for farmers is clarified.