Some 125 jobs are being lost in Co Tipperary with the closure of the SunPharma Ranbaxy Pharmaceuticals plant in Cashel.
The facility is ceasing operations on April 28 and will close completely by the middle of May.
Independent TD Mattie McGrath said it was terrible news for the local area.
"This is a massive blow for the workers and their families," he said.
"In some cases, husbands and wives are working there, partners - they're long-standing, good employees, good employers as well.
"It's a major body blow to a town like Cashel."