Irish airline Aer Lingus said it was "at a loss to understand" why staff plan to go on strike next month in a dispute over a pension fund shortfall.
Unions representing administrative staff as well as cabin crew estimated on Tuesday that up to 3,000 workers might join the first of what could be a series of stoppages to force the airline to provide more cash.
"Aer Lingus believes that its proposal comprehensively and sustainably addresses pension provision for affected Irish Airlines Superannuation Scheme (IASS) members (including Aer Lingus employees) and is based upon prudent investment and other assumptions," the airline said in a statement on Wednesday.
In the event of strike action being taken, the airline said it might hold "union groups and all relevant officers and officials personally liable in respect of the losses" sustained by Aer Lingus.
The Aer Lingus staff pension scheme, which also covers workers at the Dublin Airport Authority, had a EUR€700 million (USD$904 million) deficit at the end of last year.
Aer Lingus says it is not obliged to pay more into the fund but has been holding talks with unions for months about the shortfall in an effort to avoid industrial action.