Staff from Cardinal Health in Co Offaly have been called to a meeting by management tomorrow morning.
In an email to staff the company said it was closing operations from 4pm this afternoon until tomorrow morning to facilitate all staff attending the meeting.
It is understood between 350 to 400 people are currently employed at the medical devices manufacturing company at Sragh Industrial Estate in Tullamore.
RTÉ News has requested a comment from the company but has not yet received a response.
A Siptu spokesperson said they received a formal invite from Cardinal Health’s management to attend tomorrow’s meeting with staff.
Approximately 280 Siptu members work at the site and a union representative is meeting with members ahead of the meeting.
The company was originally set up as Sherwood Medical in 1982 but has changed hands multiple times over the years and now owned by Cardinal Health.
At its height, over 600 employees worked at the site, and it has been a huge contributor to the local economy.
In 2012 there were 150 job losses, and over the years the company has also sought voluntary redundancies.
Fianna Fáil Cllr Tony McCormack said he was contacted by a number of concerned employees.
He said they will have to wait and see what tomorrow’s meeting brings but he was concerned that news of staff being sent home today "didn’t read very good".
"Potentially there will be job losses, or in the worst-case scenario a planned shutdown. This company has been a huge contributor to the local economy.
"My thoughts this evening go out to the families and the employees as they ponder what tomorrow's meeting might bring."
Cllr McCormack said he will be contacting the Tánaiste and the Minister for Enterprise, Trade and Employment Peter Burke to make sure the employees are looked after if there are job losses.
He also said he would work with the IDA in whatever way they can to make sure the plant is filled with another company if there is a worst-case scenario.
"It's a sad day tomorrow. It's a sad day for the employees as they ponder what the future might bring."
