Unions FILT-CGIL and UIL Trasporti said they were seeking improved pay and conditions after staging a four-hour stoppage earlier in June.

Ryanair workers in Spain and Portugal have announced strikes for late June and the Italian unions said they also expected stoppages in France and Belgium.

Labour unrest and staff shortages in Europe are causing headaches for travellers heading into the peak summer season, with airports and airlines clamouring to find more workers, minimize cancelled flights and reduce delays.

Ryanair ranked first for the number of passengers travelling to and from Italy last year as Alitalia shrunk its network before handing over to smaller ITA Airways.

(Writing by Keith Weir, editing by Maria Pia Quaglia)