Crew of the airline operating the Kerry-Dublin route are to ballot for industrial action.
Stobart Air cabin crew are involved in a dispute with the company over union recognition rights.
The Fórsa trade union says the ballot of members will close next week.
Stobart Air has been operating the Kerry-Dublin Public Service Obligation (PSO) route for Aer Lingus Regional since 2015.
It operates daily morning and afternoon flights to the capital from Farranfore, which return each afternoon and evening.
The Fórsa trade union says Stobart Air has refused to negotiate with them on pay and conditions of crew that are based in Dublin and Cork.
Head of Communications at Fórsa, Bernard Harbor says they’re currently balloting members and this will close on the 10th of April.
If members vote for action, only then will they know what form the industrial action will take.
He says there’s a very strong chance the Kerry-Dublin service would be affected but no decision has been made.