Siptu has applied to the Irish Congress of Trade Unions (Ictu) for an all-out picket at Aer Lingus.
The move follows warnings by the airline that it will suspend 1,800 ground operations staff and cabin crew, who are members of Siptu, from next week unless they provide written undertakings that they will not take part in industrial action planned by the union.
Siptu national industrial secretary Michael Halpenny said last night that the action by Aer Lingus represented "an attack on the fundmental rights of workers".
"Aer Lingus employees have the right to freedom of association, to be represented by a trade union and to undertake industrial action, if necessary, in order to protect their working conditions. The application for an all-out picket is also in line with the deliberations of Monday's meeting by Aer Lingus shop stewards when it was decided to take industrial action on November 20th and 23rd.
"I have written to Congress this afternoon to seek an all-out picket, in the event that it is needed. Our members will not be intimidated out of maintaining their right to collective bargaining," Mr Halpenny stated.
Ictu is expected to consider the application for an all-out picket next week if the industrial action at the airline goes ahead. It will ask other unions such as Impact, which represents pilots and cabin crew, and the craft unions for their views.
Aer Lingus did not comment last night on Siptu's move. It said it was working to resolve the issues and was confident that its flights would go ahead as scheduled next week.
Siptu has served notice on Aer Lingus that it will engage in rolling four-hour work stoppages on Tuesday and Friday next week in protest at moves by the airline to implement a €20 million cost-cutting plan.
In October, Aer Lingus introduced a pay freeze for all staff until its costcutting plan, the Programme for Continuous Improvement (PCI), was implemented in full. It says costs and working practices in the airline are out of line with industry norms.
Earlier this month, it announced that the contracts of temporary staff would be terminated in January and all new staff would be employed on revised terms. Siptu says staff could lose up to €5,000 under the contracts.
The company has offered compensation to workers affected by cost-cutting proposals.
In a letter sent to Siptu members at the airline on Tuesday, Aer Lingus chief executive Dermot Mannion said that any employee who participated in the industrial action next week "may be guilty of very serious misconduct in the discharge of their duties".
He said that for nearly a year the union had refused to engage meaningfully with the company on its PCI plan.
He asked staff to confirm in writing by Monday evening that they would not take part in the planned action.
"Aer Lingus is unwilling to accept partial, incomplete or interrupted discharge by you of your duties as an employee of Aer Lingus and if that were to occur, Aer Lingus will exercise its legal entitlement to suspend you from the payroll," he said.
