SIPTU members employed at Carroll’s Cuisine in Tullamore, Co Offaly are taking strike action in a dispute over pay and union recognition.
SIPTU has around 100 members at the plant, which produces cooked meats and ready meals.
The workers began a 12-hour work stoppage at 7am, with another 12-hour stoppage planned for tomorrow.
Pickets have been placed at the entrances to the plant.
SIPTU has accused management of withdrawing from talks concerning pay and conditions.
Sofina Foods, the parent company of Carroll’s Cuisine, said it acknowledges the tensions at its Tullamore site and recognises that it has "fallen short of our own high standards in supporting our colleagues - particularly in listening to and acting on their concerns promptly."
"For this, we apologise," a spokesperson said.
"We would like to thank the SIPTU trade union for the open dialogue we have maintained throughout what has been a difficult period for our people," they said.
Sofina Foods said it remains fully committed to addressing the concerns raised, including those related to pay and working conditions.
"Last week, we held a significant number of direct meetings with our approximately 200 colleagues at the site, during which we shared a clear process and timeline for proposing and agreeing improvements," the company said.
"Next week, we will meet with our Employee Relations Group to discuss these proposals in detail," it added.
Referring to the industrial action taking place today and tomorrow, Sofina Foods said that while it is not the outcome it had hoped for, and will affect its ability to serve customers, it respects the right of individuals to express their views.
"Our focus remains on maintaining a safe, supportive workplace and ensuring continuity of supply for our customers and consumers," a spokesperson said.
"To help achieve this, we have implemented robust contingency plans to minimise disruption, including additional shifts and prioritisation of key product lines to maximise production," the company added.
