Oslo  - An estimated 17,000 airline passengers were stranded Friday due to labour action by employees of Norwegian civil aviation authority Avinor.

Among the five airports closed over the wage strike were Bergen, Molde and Kristiansund. Strike action did not affect Oslo's Gardermoen airport, the country's largest.

Some 200 Avinor employees went on strike after mediation efforts overnight Friday failed, forcing the airport closures since there was insufficient staff to respond to possible emergencies or fires.

Military, rescue and air ambulance flights were slated to operate as usual.

Airlines SAS, Norwegian and Wideroe said they were trying to help to rebook passengers and were considering to ferry passengers by train or bus to airports that remained open.

Passengers were advised to consult websites operated by the respective airlines over cancellations.

The strike action occurred on a busy travel day as many people were planning to take part in the constitution day celebrations on Saturday May 17 that marks the 1814 signing of Norway's first constitution, and the end of over 400 years of Danish rule. (dpa)