Forsa is to ballot Aer Lingus cabin crew on management's proposals for sweeping changes to their working conditions.
The union says what is being put forward is effectively an alternative to lay-offs and a further significant pay cut to 30 percent of pre-coronavirus rates.
It will hold the ballot over the next few days after a meeting of its Cabin Crew Branch Committee today.
The union will not be making a recommendation on how to vote but will make it clear the alternative to this package is lay-offs and further reductions in pay.