Aer Lingus has said it cannot guarantee that it will be able to operate all of its flights from Wednesday, when strike notice from Siptu takes effect in a dispute over new work contracts.
In advance of a meeting this evening of Siptu officials in the airline, Aer Lingus has told passengers intending to fly with the airline that disruption on Wednesday, Thursday or Friday must be considered a possibility.
Siptu national industrial secretary Michael Halpenny declined to say what form of action the union's 1,800 staff at Aer Lingus would take if the airline's position on new work contracts did not change.
"If the company proceed as they have done, then we have said publicly that we will react," he said. "We've always said that as far as industrial action is concerned it is a reaction to the actions of the company."
The union will consider its position at the meeting this evening, which will be held at Dublin airport. Asked whether he had anything to say to passengers facing disruption due to the threatened action, Mr Halpenny said: "It's up to the company to say because they're the people pulling the trigger."
Aer Lingus, which says the current work practices of its staff are uncompetitive, told passengers that it will change their flights free of charge if they wish to avoid the threat of action this week. Passengers who wish to change their tickets were advised to phone 0818-365000 or use the airline's website, aerlingus.com.
The airline said last night that there was no change to its position.
Asked what form the industrial action might take, an airline spokesman said: it does not know for sure. "A strike mandate from employees does exist."
Mr Halpenny did not know of any behind-the-scenes efforts to broker a settlement in the dispute. He said he hoped that people in Government circles were taking note of the situation.
"The strike notice runs out for Wednesday. On the same day the company are threatening to suspend people for not co-operating in training new employees who have been brought in on the basis of these inferior contracts. The following day is the day on which the company has threatened to bring in new contracts for existing staff."
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 bank holiday work.
