Management at Shannon airport has issued notices to 23 contract staff informing them that their employment contracts will not be renewed when they expire in March.
The move is the first in a series of direct cost-cutting measures planned by management to stem losses at the airport.
Earlier this week, workers were informed by management that that a "generous" €35 million restructuring plan for Shannon, which they rejected in January, had now been withdrawn.
The plan was aimed at introducing savings of €10 million annually at the airport and would have led to about 200 voluntary redundancies.
Siptu described today's move as "provocative and grossly unfair to the individual contract workers concerned", who are employed in various catering roles at the airport.
"These workers are being used as pawns in a battle by management to cut costs at Shannon regardless of the consequences for individual employees," Siptu's national industrial secretary, Michael Halpenny, said.
He called on Dublin Airport Authority Shannon to rescind the notice and to concentrate their efforts on the Labour Relations Commission engagement that all parties have now committed to.