Transport Minister Noel Dempsey says he is seeking legal advice in relation to Ryanair's decision to reduce its Kerry to Dublin service.
Ryanair announced last week that it was reducing its frequency of daily flights between Kerry and Dublin from three to one from the end of October.
Business leaders and public representatives in Kerry have said that the decision will have a negative impact on attracting business to the county.
In 2008 Ryanair had agreed to a three-year contract to provide the service and was receiving a public service obligation (PSO) subsidy worth €1.7m a year.
The Minister said today that he was very annoyed at the decision. Minister Dempsey said that Ryanair should have given a minimum of three months notice and he asked Ryanair 'to stick to that so the Department could come up with alternative arrangements'.
He added: 'I have asked the Department to take legal advice on the contractual matter where Ryanair have withdrawn the service or threatened to withdraw the service without having given the proper notice.'
No Ryanair comment on French court report
Ryanair says it has not received any formal notification from French authorities in relation to reports that it has been indicted for illegal work practices.
The airline said it would not comment on reports in the French media which it described as 'rumour or speculation'.
A spokesperson referred to a statement issued last May in relation to the allegations about Ryanair employees' contracts and their tax arrangements at their Marseille base. Ryanair has stationed 120 pilots and cabin crew in Marseille since 2006. The airline's statement reiterated its belief that all Ryanair employment contracts comply with EU law.
The airline claims that the activities of Ryanair's employees take place on Irish registered aircraft, which are thus Irish territory and not 'in France' under the EU Transport Workers Regulations.
It said all were employed under Irish contracts, paid in Ireland, and pay full labour taxes, social security and their pension obligations in Ireland.
It said there was no truth in allegations that Ryanair was engaging in clandestine work, illegal labour or social dumping.
It said Ryanair was currently taking an action in the European Court of Human Rights against France to challenge a 2007 decree which attempted to impose what the airline called unfair and restrictive legislation on international transport companies in France.
In the same statement in May, Ryanair threatened to shut its Marseille base if the Aix-en-Provence Prosecutor's Office launched court proceedings challenging its employment practices.
French prosecutors are reported to have charged Ryanair with illegal working practices after the airline declared 120 employees in France as working in Ireland.
A legal source said the charges, brought on Monday, related to several labour laws - including those banning concealed employment, preventing workplace councils from operating and preventing access to unions.
Employees living in France should be declared in France, say the unions who lodged the legal complaint. Ryanair has its French hub in the Mediterranean city of Marseille, with four aircraft.