Travellers to and from Spain could face significant disruption from next week as air traffic controllers begin indefinite strike action across the country. The action by ATCs at SAERCO-run towers is expected to affect 14 airports nationwide from Friday, March 17, including several in the Canary Islands.

Airports expected to see delays on flights to and from the UK, inter-island travel and international flights, including those in Lanzarote, Fuerteventura, La Palma, El Hierro and La Gomera, as well as several on the mainland, including Madrid. The strikes are expected to begin at midnight on April 17 and have been organised by Union Sindical de Reguladores Aereos and Comisiones Obreras. Working conditions, stress and shift pattern changes have led to a point that "aeronautical safety cannot be sustained," the unions said in their statements.

One of the major concerns highlighted by the unions is the failure by SAERCO to provide breaks and cancelling previously approved holidays. The problems have been building up for several years, according to EuroWeekly.

Passengers travelling during the strike period have been warned to prepare for flight delays and possible cancellations, short-notice schedule changes and longer waiting times at affected airports. As air traffic control strikes are classed as "extraordinary circumstances", airlines are not usually required to pay compensation for delays or cancellations, although they must still offer rebooking or refunds.

This comes as other strike action also continues to grip several major Spanish hubs. Since March 30, Barcelona-El Prat Airport, Adolfo Suarez Madrid-Barajas Airport and Palma de Mallorca Airport have been impacted by strike action, involving Groundforce workers, with stoppages occurring in several intervals - from 5am to 7am, 11am to 5pm and 10pm to midnight - on Mondays, Wednesday and Fridays.

This action reportedly could continue indefinitely and stems from ongoing pay disagreements. The stoppages have created long queues, delayed luggage drop-offs and boarding issues.

Spanish airport operator AENA released a statement which said: "Indefinite strike called by Groundforce staff, a company providing services to various airlines, starting on Monday, March 30.

"Partial work stoppages have been called on Mondays, Wednesdays and Fridays during three time slots: 5-7am, 11am-5pm, and 10pm-midnight.

"If you're planning to fly, check to see if your airport is affected. Contact your airline to find out the status of your flight."

The Express has contacted SAERCO for comment.