A number of Irish-based Ryanair pilots are to take pre-Christmas strike action following a dispute over winning independent representation for pilots in the company.

The one-day industrial action will take place on Wednesday December 20 and will mostly involve captains.

Trade union Impact said it would either disrupt flights or generate substantial costs for the airline.

Pilots from the Irish Airline Pilots' Association backed the industrial action overwhelmingly during secret ballots.

Although the number of employees involved in the strike is fewer than the total number of Irish-based Ryanair pilots, the action will have impact because planes cannot legally or safely fly without a captain, the union added.

Impact official Ashley Connolly said Ryanair was the only Irish-based airline that refuses to recognise independent pilot representatives.