The Irish Thalidomide Association is taking its case to the High Court in a bid to gain compensation for Thalidomide survivors.
Anti-nausea drug Thalidomide was introduced in the late 1950s and administered to pregnant women suffering from morning sickness. The drug was later found to be the cause of many different birth defects.
In 1975 an agreement was made between the Irish and German governments for compensation payments to survivors in Ireland, but was never formally approved by the High Court here. Germany cannot therefore be forced to make the payments.
Dr Austin O'Carroll of the ITA said the group now faced losing the small compensation they receive because of the legal action.
"We've been six years campaigning...for full and fair compensation," he said. "The Government has made repeated promises, but has failed to enforce (them) and has forced us to take legal action.
"Our entitlement to the present pension and any future entitlement is at threat because we are seeking compensation."