Aer Lingus management and unions resumed talks today on a cost-cutting programme and changes to working practices.
Management warned about 1,500 pilots and cabin crew earlier this month that they face having pay increases due under the national agreement withheld permanently if they do not agree on changes to working practices by today.
It appears increasingly unlikely that today's deadline will be met.
In a letter to the trade union Impact, the company said if agreements on change were not reached by the end of January it would deem outstanding payments due under the national agreement to be the contribution of pilots and cabin crew towards the airline's overall cost-saving programme.
Impact described the airline's move as "a stunt". A spokesman said the company had no authority under the national agreement to keep pay increases due to staff.
Aer Lingus has been negotiating with trade unions for months on a reform plan, known as the Programme for Continuous Improvement and aimed at generating annual savings of €20 million.
The company introduced a freeze last October on paying two phases of the national agreement, due last autumn and in April, until progress was made on the cost-saving plan.
As part of talks brokered by the National Implementation Body before Christmas following several strike threats by workers, the company and Siptu have been examining cost-savings worth about €10 million.