Bord na Móna is to offer a voluntary redundancy package to staff in its horticultural business, which employs around 170 people.
As part of the restructuring, the Cuil na Móna plant near Portlaoise, which employs around 55 people, is to close. The workers there will also be offered the option of transferring to other facilities at Kilberry, Co Kildare and Ballivor, Co Meath.
A statement said the company was carrying out a 'comprehensive evaluation' of the division as part of a review of all of its businesses. The horticultural business includes the Shamrock brand.
'Taking a tough decision such as this now provides a platform to ensure that Bord na Móna continues as a leader of quality horticultural products both at home and abroad,' said chief executive Gabriel D'Arcy.