Aer Lingus is planning to recruit more than 300 pilots and cabin crew this year to enable it expand its long-haul services and open its first base outside the Republic.
All of the staff are being issued with new contracts, which are the subject of a dispute with Siptu and other trade unions involved with the airline.
The new contracts would mean staff would have reduced holiday entitlements, while allowances and working hours would also be altered.
Entry-level pay for cabin crew is €22,500, rising to about €30,000 when allowances are added. About 14 cabin crew are graduating from training each week.
The new staff are needed for Aer Lingus to expand its long-haul services. The carrier will take delivery of two new A330 aircraft for use on these routes in May and June. Aer Lingus is hoping that a new open skies bilateral agreement between the European Union and the United States will have been agreed by then to allow it open new transatlantic routes.
If those talks fail, the airline will expand its services on existing routes to New York, Boston, Los Angeles and Dubai.
Aer Lingus is also expected to establish a base in the UK to provide flights between British airports and to continental Europe from next January. It will take delivery of two A320 aircraft in December for these services.
The move will increase Aer Lingus' staff numbers by about 8.6 per cent from its current level of about 3,500.
It already has about 1,000 cabin crew, the majority of whom are represented by Impact, which also acts for its pilots.
Impact, which represents about 1,400 staff at Aer Lingus, is currently in talks with the airline over the introduction of the new contracts under the auspices of the Labour Relations Commission (LRC).
Siptu, which acts for 1,800 Aer Lingus workers, and craft unions this week issued the company with notice of their intention to take industrial action by the end of February.
Aer Lingus introduced the new contracts for staff joining from February 1st. It plans to issue the contracts to existing employees on March 1st. It is understood that the airline will make renewed efforts to resume talks with Siptu next week, possibly under the umbrella of the LRC.
Siptu has so far refused to enter talks until the company suspends plans to introduce the contracts.
"The ball is in their court; there's no more we can do," said Michael Halpenny, Siptu's national industrial secretary.
