Siptu said today it is seeking a meeting with management at the Woodfab Timber plant in south Wicklow over staff losses following a fire at the premises on Sunday.
Gardaí are continuing to investigate the cause of the fire amid suggestions it may have been started deliberately.
The fire caused serious damage to the plant’s main production line. The plant, which employs 65 full-time staff and a further 70 contract workers, is located on the outskirts of Aughrim.
Most of the staff at the plant are currently on annual holidays and the production units were closed for annual maintenance when the fire broke out.
Siptu branch representative Kieron Connolly said today the union had been informed the majority of workers at the plant would lose their jobs as a result of the fire.
Mr Connolly said it was believed a small number of jobs would be retained at the site.
Woodfab Timber produces fencing and decking products for Irish and British markets. It is a major supplier of roadside post and rail fencing and has developed acoustic timber fencing for use as sound barriers, particularly on roadsides.
While the company has said the building was insured, concern locally centred on damage to export markets which may be caused by any delay in rebuilding.
Local estimates yesterday put the value of the damage in millions of euro. The main production sawmills, the hub of the plant, was burnt in the blaze, which was spotted by a local taxi driver about 1.30am on Sunday.
Firemen from nearby towns of Rathdrum, Tinahely, Carnew and Arklow fought the fire for several hours.
The blaze took more than 10 hours to put out, but firemen succeeded in preventing the flames spreading to other plants and offices in the factory compound.