Up to 60 temporary jobs will be lost at Bombardier manufacturers in the North.
The agency posts are within the Canadian-owned aviation firm’s complementary labour force.
The move follows an assessment of customer demand.
The firm said: “Our manpower situation is kept under constant review. We have reviewed our latest requirements based on current customer demand and, as a result, will be making adjustments to the composition of our complementary labour force, who work alongside our permanent employees.
“We have informed the provider of our complementary labour force that we need to release approximately 60 people from particular assignments with us.”
Davy Thompson, regional coordinating officer at Unite the Union with responsibility for the workforce, said manufacturing was facing major challenges.
He said: “These job losses would be another blow for the Northern Ireland manufacturing sector and come on the back of significant job loss announcements elsewhere across Northern Ireland at the end of last year.
“This announcement highlights the scale of the ongoing challenges facing the sector.”
He said not enough is being done to ensure that the jobs being lost in the manufacturing sector are replaced with positions of a similar standing.
Unite will be holding a rally in Ballymena, where several major manufacturers including JTI Gallaher tobacco factory have recently announced closures, on Saturday February 6.
Mr Thompson said it would “offer our members, young people and the local community an opportunity to vent their frustrations against what they see as a total failure of Stormont to introduce a relevant and cohesive approach to manufacturing within Northern Ireland”.
Ulster Unionist Stormont assemblyman Andy Allen said the news will be devastating for those workers affected.
“Manufacturing in Northern Ireland has been hard hit and we now need to see urgent action to put an end to the stream of announcements of job losses in the sector.
“We need to see the Executive acting to improve job security. We cannot afford to continue to lose skilled workers from Northern Ireland’s labour force.”