Aer Lingus passengers face further disruption this week as the second one day stoppage by clerical and operative staff looks set to go ahead on Friday.
SIPTU's National Industrial Secretary Mr Noel Dowling, said talks earlier today with the company had not made any progress, and the union was "left with no option" but to proceed with their 24 hour stoppage which will begin at midnight on Thursday and continue until midnight on Friday.
In a statement, Aer Lingus said further strike action was damaging to customers, employees and the company.
A spokesman said, "with pay settlements agreed only 10 weeks ago and the airline under increased pressure in the marketplace, SIPTU's decision to close the airline for the second time in a week defies logic."
But Mr Dowling said the airline said it could not meet the staff's claim for pay parity, despite accepting and implementing two agreements with SIPTU last November and December.
These agreements were accepted "in the full and clear knowledge of the conditions which we set, namely that if any other grade got a substantial pay increase without having to give productivity in return, SIPTU would seek exactly the same for its members," Mr Dowling added.
Aer Lingus said the current pay settlements are fair and equitable to each group and involve substantial improvements in pay and conditions.
The company also warned that competitiveness at the airline is under "serious threat" as a result of the impact on travel of the foot-and-mouth restrictions and rising costs as a result of previously agreed pay settlements.