Newbridge Credit Union Action Group say they will be challenging the takeover of the credit union by Permanent TSB.
The move was approved during an emergency sitting of the High Court last night at a cost of 54 million euro to the taxpayer.
PTSB will assume ownership and management of the members assets and liabilities and says all deposits are protected - while members are being advised that it's business as usual.
A special manager had been appointed by the Central Bank to the body in 2012 as a result of serious financial difficulties as borrowers struggled to repay large loans.
Chairman of the Newbridge Credit Union Action Group, Willie Crowley, says members will fight the takeover:
