AER Lingus introduced new cabin crew rosters today amid fears of strike action at the airline.
Management has told cabin crew they will be removed from the payroll if they fail to comply with the rosters.
The IMPACT trade union opposes the new rosters and there has been been disagreement over the issue for months, with cabin crew engaging in a work-to-rule since October 12.
The rosters move is part of a plan to cut costs at the airline, the Greenfield Cost Reduction programme, introduced last year.
About 800 IMPACT members are involved in the work to rule, with many of them refusing to work certain roster arrangements.
Today's move comes after contacts at the Labour Relations Commission on Friday failed to resolve the dispute.