Airbus SE staff at a wing-assembly plant in Broughton, Wales are set to vote on strike action after rejecting a pay offer, posing a potential risk to production as the company cranks up build rates for narrow-body jets.

Toulouse, France-based Airbus is in discussions with the Unite union to try and avoid industrial action, a spokesman said Friday. The U.K. facility employs about 4,000 staff, down from 6,000 in 2020.

The planemaker also faces the threat of walkouts in Germany over plans to hive off a parts unit. Labor groups there staged a series of strikes late last year in protest at the planned restructuring.

The conflicts come at a bad time for Airbus, which is gearing up to expand the output of single-aisle aircraft beyond pre-pandemic levels. The firm has already had issues with meeting current build rates, delivering fewer planes than planned in September and October as suppliers struggled to ramp up.

Airbus has shed about 9,000 positions since 2019, according to company figures, but now aims to hire 6,000 new staff in the first part of this year. The company said this week it will add posts worldwide and across its business units, without providing a geographic breakdown.

The Broughton staff agreed to a shorter working week in February last year to save jobs, with the agreement due to the last 18 months.