90 jobs are to be lost at QK Meats in County Kildare. The jobs will go in the plant's boning hall.
The company says the decision is part of a restructuring plan which will protect remaining jobs in its other operations.
SIPTU, which represents many workers in the plant, says it is regrettable that the company failed to engage with the union.
QK meats is part of the Queally Group which is one of the country's largest agri-businesses, employing more the 6,000 people. The group includes well known brands such as Dawn Farms, Lily O'Brien's chocolates and Glenpatrick Spring Water.
QK said boning hall operations in Ireland had been affected by the recession, the high costs of manufacturing in Ireland and the weakness of sterling.
There was better jobs news from Northern Ireland, where Seagate Technologies is to provide almost 100 jobs.
The US computer company's Derry plant will gain 85 jobs, and ten posts have been announced at Queen's University in Belfast, as part of the same project. The company, which makes computer hard-drive components, currently employs 1,400 at its site in Springtown in Derry.
