Thirty-five Glanbia employees at the Glenville factory in Waterford are to lose their jobs.
The redundancies follow the transfer of milk packing operations from Glenville to Ballitore in Co Kildare. Eleven staff will be retained at Glenville.
Glanbia operations director Frank Tobin said the decision was taken in the context of "ever-increasing manufacturing costs and the need for greater operational efficiencies".
The move followed a review of the company's liquid milk operations and was to ensure "our business remains competitive into the future".
He said it was regrettable for the employees who had made a strong contribution to Glenville.
Mr Tobin said Glanbia would be consulting with employee representatives and would provide "fair redundancy terms".