Siptu's 1,800 members at Aer Lingus are preparing to withdraw their labour from March 1st, if the airline does not back down on plans to introduce new contracts for existing staff.
The trade union has formed an 11-member disputes committee comprising shop stewards at Dublin, Cork and Shannon airports, and union officials.
It is understood that the shop stewards will meet next Monday evening to formalise their strike plans.
"A withdrawal of labour is being planned," said a senior Siptu source. "The disputes committee will formalise arrangements for the extent and timing of our action next week."
To date, Siptu has declined to say what industrial action it would take at the airline in the dispute over the new contracts, following a vote by members to take action. It remains to be seen if it opts for a temporary stoppage or an all-out strike.
The controversial contracts were introduced by Aer Lingus for new staff on February 1st and will come into force for existing workers at the start of March.
The airline is seeking to reduce annual leave, change shift allowance payments, reduce overtime, and introduce more flexible working hours and practices. It also wants to cut time off in lieu for working bank holidays.
Siptu, meanwhile, has rejected an invitation from the airline to attend a meeting today to explore all details surrounding Aer Lingus's PCI 07 document, which covers the introduction of the new contracts.
The airline had hoped this might break the impasse between the two sides.
However, in a letter to Liz White, Aer Lingus's human resources director, Siptu branch organiser, Christy McQuillan, said the union was only prepared to enter talks when the airline had withdrawn its intention to introduce the new contracts for existing staff.
"Until the company's declarations of unilateral changes are rescinded and the terms of our agreements are again being honoured, no process of engagement can proceed in relation to PCI 07," Mr McQuillan said.
Aer Lingus said it was "disappointed but not surprised" at Siptu's decision not to attend talks.
"This would have been a good opportunity to address their concerns," the airline added.
Aer Lingus continues to hold talks with Impact, which represents about 1,400 staff, under the auspices of the Labour Relations Commission about the new contracts. Siptu said that once the breach of agreements was "satisfactorily dealt with" it was available to address the contents of PCI 07 under the umbrella of the National Implementation Body.
Meanwhile, the Impact trade union is facing a legal bill of some €700,000 after Ryanair won its appeal against a Labour Court decision to adjudicate on a pilots' dispute.
