The strikes are due to take place at Spain's largest airport on Aug. 30 and 31, the UGT union said in a statement, and would coincide with another strike planned at Barcelona's El Prat airport.

The union's main demands are more full-time contracts, training, and the use of new vehicles.

A spokeswoman for Iberia said the company was always open to dialogue and negotiation and would do all it could to avoid the strike. Failing that, the company would make efforts to minimise its impact on customers.

It was not immediately clear how many employees would be called on to participate and whether other unions were likely to join the strike.

(Reporting by Isla Binnie, editing by Andrei Khalip)