SIPTU will hold a protective ballot for industrial action at Aer Lingus over the next two weeks seeking authorisation for an immediate response to any unilateral changes sought by the airline.
In a statememt today the union said it would also put a proposal to its 2,000 Aer Lingus members not to co-operate with redundancy proposals without agreement on future plans for the company.
SIPTU is also seeking to improve its working relationship with other unions in the company to ensure a unified approach to deal with the proposed cuts."
Mr Michael Halpenny, SIPTU National Industrial Secretary, said the union had demonstrated its willingness to co-operate with change where necessary.
He added it was unclear why such drastic action was required.
The airline, which has not released details of its business plan, made no immediate comment. The airline has been realigning itself as a low-fares player following near-bankruptcy in 2001.
Aer Lingus lost business after the September 2001 attacks in the US. It has since cut costs by €344 million or 30 per cent, and axed 2,000 jobs or a third of its work force.