Ground staff at Aer Lingus have rejected the airline's €10m costcutting proposals for a second time.
The 1,800 staff represented by SIPTU have already voted to take industrial action if management attempts to implement the reforms without union agreement.
A spokesperson for Aer Lingus said the airline would consider its position over the coming days.
Aer Lingus has spent the last 15 months trying to secure €20m in staff cost savings, and has already done deals with pilots and cabin crew.
A flexibility and mobility deal for 1,800 ground staff represented by SIPTU would have delivered productivity changes including earlier start times, roster changes and transfers between different kinds of work.
There would have been no pay cuts or compulsory redundancies under the plan.
However, staff emphatically rejected those proposals a month ago.
Local negotiations and clarifications were followed by a re-ballot, but this afternoon it emerged that staff have again said no to these changes.
Under SIPTU's rules, even if there is an overall majority in favour of acceptance, if any one of the 14 sections - no matter how small - rejects the proposal, it is deemed to be rejected by all.
