SIPTU has served two weeks' notice of industrial action on Aer Lingus over attempts by the airline to "downgrade" hotel accommodation for cabin crews on New York flights.
The action could lead to the suspension of all flights, but it is expected some form of third party arbitration will be attempted before the strike deadline is reached.
The chairwoman of the SIPTU cabin crew committee, Ms Joan Loughnane, said yesterday the company appeared to have abandoned any attempt to operate a joint approach with the union to vetting suitable accommodation for staff.
The union had been forced to resort to industrial action after the company failed to respond to an invitation to attend conciliation talks at the Labour Relations Commission, she said.
"The failure to resolve this difficulty and to address a number of other issues pending in a reasonable manner and time frame is indicative of a continuing communications problem," she added.
The company has rejected SIPTU's claims that the Lucerne hotel in Manhattan, to which staff have been transferred, is not adequate to meet their needs. It has been urging SIPTU to agree to an internal arbitration framework to deal with this and other outstanding issues involving cabin crew.
As a last resort, it is likely the Labour Court will invite both sides to a hearing ahead of the strike deadline.