Seventy workers have been dismissed and another 24 temporarily laid-off, as part of a union recognition dispute at the Monaghan-based company, IJM Timber Engineering.
The company, which manufactures timber frame buildings, says it is willing to re-employ the 70 workers, but only if they are prepared to negotiate about new working hours on a non-unionised basis.
The other 24 workers will be permanently retained if the dispute can be settled, the company says.
Mr Peter McCaughey, general manager of the plant, which employs 163 people, says if production does not resume shortly it will have to close.
The union representing the dismissed and laid-off employees, the Building and Allied Traders Union (BATU) says workers will not return unless the company agrees to fully recognise its "right to represent".
A meeting of all employees involved will take place today to decide what action to take next.
The dispute arose after management attempted to secure agreement on a new system of annualised hours. Workers rejected the deal on offer which would have meant a four-day week, compared to the three days currently worked.
A series of meetings on this issue ended when workers indicated they wanted to be represented by BATU and management refused the request.
On Monday workers staged a protest outside the plant and notices of dismissal were issued by the company later that day.
Yesterday workers gathered again outside the plant.
The hopes of mediation are described as "slim" by both BATU and the management, although local TDs, Sinn Fein's Mr Caoimhghin O Caolain and Fine Gael's Mr Seymour Crawford have both offered at act as mediators.
IJM has been based in Monaghan for 33 years and is one of the largest employers in the town.
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