More than 300 people are set to lose their jobs as Cardinal Health in Tullamore, County Offaly is to close its plant by Spring 2026.
Staff were informed of the redundancies at a meeting this morning.
Management say the company plans to move its production from Tullamore to other international facilities.
Enterprise Minister Peter Burke said he will work with company management and staff.
"My primary concern is for the staff and their families who are now coming to terms with the impact of this announcement," he said.
"Following this morning's town hall meeting with staff, and along with the IDA and my department, we will work with the company management and with staff on current and potential future possibilities.
"We will make every effort to identify alternative employment opportunities for the staff affected by this announcement."
Laois-Offaly TD Charlie Flanagan described the news as a "black day" for Tullamore.
"My thoughts and solidarity are with the over 300 Cardinal Health workers and their families at this difficult time. It's a black day for Tullamore," he said.
"Relevant state agencies are on hand to provide advice and help.
"Much can happen between now and next March to soften the blow, although it is a huge setback to economic and social life of Tullamore," he added.
Cardinal Health - which is headquartered in Dublin, Ohio - distributes and manufactures pharmaceuticals, medical and laboratory products.
The company employs 315 people in Tullamore.
