SIPTU has expressed disappointment at the redundancy terms being offered to 1,100 workers who are set to lose their jobs at SR Technics in Dublin.
The aircraft manufacturing firm announced plans to close its Dublin Airport facility earlier this year due to high costs and the loss of a number of major contracts.
SIPTU says the workers have been offered a €48m redundancy package, which will only fund three weeks' pay per year of service.
The union says this is a breach of an existing agreement with SRT which entitles workers to six weeks' pay per year of service.
Further talks between unions and management are due to take place early next week.