Ryanair has argued in court that balloted strike action from some of their pilots was unlawful.

The High Court in Dublin heard arguments from a major Irish pilots’ union and Ryanair in a debate over proposed strike action.

The airline is seeking an order against Forsa, which is the parent union of the Irish Airline Pilots Association (Ialpa), in a dispute over pay and conditions.

Forsa is contesting the airline’s application for an injunction preventing around 180 pilots based in Ireland from going on a 48-hour strike from midnight on Thursday.

Justice Denis McDonald began hearing arguments on Monday from Ryanair’s legal representative Martin Hayden SC.

The airline claims strike action would be in breach of an agreement both parties signed up to in the summer of 2018 through mediation in the Workplace Relations Commission through then-chairman Kieran Mulvey.

The airline also argues that Forsa’s ballot and the subsequent notice of strike action was unlawful, and that the 2018 agreement is a “binding conclusion” and “over-arching”.

Mr Hayden told the court that Forsa has not actually quantified what it is claiming for and Ryanair, although “not indisposed to making an offer”, is prevented from doing so in the absence of such a request.

“To make a counter offer you need to have something to counter,” he said.

Justice McDonald disagreed with this assertion, arguing that this is not backed by Mr Mulvey in his report, but Ryanair’s understanding of his report.

“I’m not asking for your understanding, I’m not seeing anything from Mr Mulvey saying Ryanair cannot make a counter proposal without further information from Forsa,” Justice McDonald said.

Mr Hayden said the “damaging strikes” would not only affect Ryanair as a company, but many customers.

“If I could say this, this is ultimately a pay request… that the go-to moment is a strike, it’s a disproportionate response,” he said.

Forsa says 94% of its members who took part in the vote chose to back a strike.

Only pilots directly employed by Ryanair took part in the ballot, with those on agency contracts not eligible to vote.

If strike action does go ahead, only those with Ryanair contracts will take part and pilots on different contracts will continue to work as normal.

It is predicted that any industrial action will cause huge disruption during the busy summer holiday period.

The hearing adjourned late on Monday afternoon and will resume on Tuesday morning, however a judgment is not expected until Wednesday, as Justice McDonald predicted he would need to “reflect” on the matter.

The court will hear arguments from Forsa’s legal representatives on Tuesday.

Meanwhile, the British Airline Pilots Association (Balpa) said on Monday that because Ryanair has “wasted time with unnecessary court action”, their chance to resolve the dispute involving their pilots has been lost.

Ryanair is seeking a High Court injunction on Wednesday to stop strike action by their UK pilots.