Nearly €1bn has been wiped off the value of agricultural land around the country because of EU laws to protect the endangered hen harrier, farmers claim.
armers say the EU directive designating special protection status for the endangered raptor means they are forced to leave land unproductive.
Under the EU Birds Directive, about 169,000 hectares (up to 500,000 acres) of land in nine counties have been designated as Special Protection Areas (SPAs) to protect the habitat of the harrier, which nests on moors and rough pasture.
But more than 4,000 farmers whose land has been designated SPAs claim their farms have been effectively devalued by €980m.
"You cannot improve the land while it is designated SPA and so it as worthless as swampland," one farmer told the Sunday Independent.
In recent weeks, hundreds of farmers have joined the lobby group Irish Farmers with Designated Land (IFDL), in a bid to urge the Government to either compensate them for their land or veto the designation altogether.
The lobby group was formed by Cork farmer Jason Fitzgerald last August but gained new impetus in recent weeks with two new chapters established in Tipperary and Offaly-Laois over the past fortnight.
Farmers claim that restrictions on farming practices in SPA-designated land means they cannot farm the land - nor sell it because it's worthless to other farmers.
"Having the designation is like having a stigma attached to it," Mr Fitzgerald told the Sunday Independent.
Cork auctioneer and chartered surveyor Joe McCarthy said uncertainty over SPAs is creating huge headaches for land vendors and potential buyers.
"These lands are immediately ruled out for forestry and have limited agricultural use. Our experience tells us that if the land was available for planting it could achieve €3,750/€4,000 per acre. Unfortunately at the moment, the uncertainty on the SPA payments going forward, land is practically unsaleable until these issues are clarified," he said.
SPAs were designated in 2007 covering lands in counties Clare, Galway, Tipperary, Limerick, Cork, Kerry, Laois, Offaly and Monaghan, and farmers were subsequently offered a compensation package by the Department of Agriculture.
But the scheme closed in 2010 as a cost-cutting measure, even though only 377 affected farmers availed of it, leaving 4,400 farmers with no compensation and severe restrictions on their land.
Since then, the department has offered affected farmers payments of up to €5,000 per farm under its five-year GLAS (Green, Low-Carbon Agri-Environment Scheme) rural development programme.
MEP and former GAA president Sean Kelly said the policy is unfair to farmers and he is urging the Government to restore the compensation scheme. "It's not sufficient, especially for those who lost out when the compensation scheme closed," he said.
The original scheme was so confusing, farmers didn't apply for it before the deadline.
"They weren't aware of the consequences until it was too late," Mr Kelly added.
He said he will continue to press for change at EU and national government level.
"I don't want to give false hopes, but a lot of TDs have concerns over this and so do I," he added.
A spokesman for the Department of Arts, Heritage and the Gaeltacht, which is responsible for the National Parks and Wildlife Service, said an inter-departmental group is drafting a Threat Response Plan for the hen harrier, which will also examine "issues of concern for landowners and farmers".
But there is no compensation scheme currently being considered aside from the GLAS programme, he said.
He also ruled out Ireland exiting the SPA designation scheme in light of an ongoing European Court of Justice litigation known as 'The Birds Case' in which Ireland was found to have inadequately provided for the protection of wild birds in 2007 and was subsequently ordered to designate six SPAs to protect the hen harrier.
"The Birds Case remains open, with the possibility of return to the court and fines being imposed on Ireland if we are not seen to be in compliance with the judgment. Given the obligations arising from EU law, the department is not in a position to consider the de-designation of these important sites," he said.