Bord na Móna is to lay off 78 seasonal workers with immediate effect and temporarily lay off another 72 permanent workers from next Thursday.
The layoffs are the result of a decision by the ESB to suspend the operation of its peat-fired power plant at Lough Ree in Co Longford.
The decision was taken as a consequence of legal proceedings against the plant taken by the Environmental Protection Agency.
The EPA has begun a prosecution because the temperature of cooling water discharged from the plant into the river Shannon is too high.
The Lough Ree power plant will remain off line for an undefined period of time according to the ESB.