A west Clare community is fighting to save its 500-year castle from falling into the Shannon Estuary.
A Department spokesman said yesterday any remedial conservation works necessary would be discharged this spring.
Built in the 15th century by the MacMahon clan, the castle is situated on the water's edge at the village of Carrigaholt.
The Government has been notified of concerns raised by two engineers who believe the castle is being eroded by the sea.
Col Frank Blake, a retired Army engineer from the area, has written to the Minister for Arts, Heritage, Gaeltacht and the Islands, Ms de Valera.
He said: "It is my opinion that action must be taken as soon as possible by the responsible authority to extend the sea wall to preserve this important and historic castle."
Another engineer who carried out a survey for the Office of Public Works in the mid-1990s came to a similar conclusion.
Mr Vincent Flynn, chairman of Carrigaholt Development Association, said the Department had failed to respond to those concerns. He was told a Department engineer's report had found the castle was in no immediate danger.
The building commands a view of the mouth of the Shannon, and is the first landmark visitors see coming into the village, but there is continual erosion at its base.
"It would be a terrible tragedy if we woke up some morning and saw the castle tumbled," Mr Flynn said. "It guards the lovely secluded bay and is part of our heritage. We made representations to Minister Síle de Valera as it is part of her portfolio."
The Department spokesman said Ms de Valera was satisfied the castle was not facing an immediate threat from coastal erosion, but any remedial conservation works necessary would be carried out this spring.
"This work had been pencilled in for summer, 2001, but could not proceed because of the threat of foot-and-mouth; and given the exposed nature of the site, particularly from a health and safety perspective, the work could not be programmed for the winter months."
About 30 years ago the Office of Public Works performed a strapping operation with steel and stone when a split appeared on one side.
Mr Flynn added: "We are monitoring the situation and we want the Minister to take a deeper interest in the castle. Visitors and locals are astounded that there is no action and there is great disappointment that there is no movement on the issue."
The castle was built about 1488 as the principal residence of the MacMahon chiefs of Corca Baiscinn, the Gaelic name for west Clare, and it eventually fell into the hands of the Earl of Thomond, Donal O'Brien.
Meanwhile, the Dromineer and District Development Association in Co Tipperary has secured a €31,744 grant from the Department of the Environment to conduct work on the 16th-century Lakeside castle's deteriorating structure.
Located on the shores of Lough Derg, the association is seeking additional funding to restore the ground floor of the castle to house items from the area currently displayed in the National Museum.