SIPTU has hit out at SR Technics following the company's rejection of Labour Court recommendations published yesterday.
The court wants the Swiss-owned aircraft maintenance firm to fund deficits in its pension funds and to double the funding available for its redundancy package.
The company is closing its facility at Dublin Airport later this year with the loss of more than 1,100 jobs.
It claims it is not in a position to increase its redundancy package or to finance any pension fund deficit because it is limited by commercial constraints.
Unions at the company are due to consult their members today to formulate a response, but SIPTU has already expressed disappointment at the SRT stance.
It has accused the company of treating the workforce, the Labour Court and the Labour Relations Commission with disrespect.