Forty Bord na Móna workers based at the ESB Lough Ree Power Station in Co Longford have been suspended after unofficial industrial action.
The power station has been closed for three months due to extensive repairs after a serious problem with corrosion.
It is due to re-open next week and Bord na Móna says it was taking action because of the failure of the workers to comply with instruction to return to their duties in bringing peat into the station.
An unofficial dispute is under way as the workers claim they are owed money for loss of earnings during the period when the power station was closed.
The dispute does not pose a threat to power supplies as the station is still off the national grid.
