A provisional liquidator was appointed to the pharmaceutical company on Tuesday with the 130 workers told at lunchtime to clear out their lockers.
The plant was bought last year by Slovakian based Saneca Pharmaceuticals from German holding company Mutares AG.
The closure was raised with the Minister for Jobs, Enterprise and Innovation in the Dáil last evening by TDs Mattie McGrath and Seamus Healy.
Minister Mary Mitchell O'Connor sympathised with the workers at but said the closure was indicative of changes in the pharmaceutical industry.
She said despite the best efforts of her department, Saneca felt they had no option but to call in a liquidator.
However, Deputy Mattie McGrath raised questions about the Competition Authority's involvement in the decision to sell Suir Pharma to Saneca in the first place.
