The High Court will give its decision tomorrow morning on an application by Ryanair for an injunction restraining some of its Irish-based pilots from striking later this week.

Mr Justice Denis McDonald said he was acutely conscious that there were many people in Ireland and abroad concerned about their travel plans.

However, he said he needed some time to collect his thoughts around the arguments made by the legal teams for the airline and the pilot's union Fórsa over the past two days.

There are 180 pilots, who are members of the Irish Airline Pilots’ Association, a branch of the Fórsa union, planning a work stoppage on Thursday and Friday in a dispute over pay and conditions.

It follows the completion of a ballot in which a majority of the members of the union who were entitled to vote backed industrial action.

The strike, if it proceeds, has the potential to disrupt the travel plans of thousands of Ryanair passengers flying into and out of Ireland if flights have to be cancelled.

This afternoon, having earlier heard submissions from Ryanair's legal team, the court heard detailed arguments from Fórsa.

Marguerite Bolger, SC for the union, told the court the use of Kieran Mulvey as mediator for its current pay claim should not be seen as a connection to the 2018 agreement between the union and the airline.

It specifies that industrial disputes related to certain topics should go to mediation and fully through a dispute resolution process before industrial action can be taken.

"Just because it is the same mediator does not mean my clients were buying into the dispute resolution process set out in the 2018 agreement," she said.

Ms Bolger also took issue with Ryanair’s comments that the union’s pay claim lodged in March was a "purported" pay proposal.

It is a pay proposal, she told the court, covering a range of areas such as pay structures, pensions, maternity and paternity pay, holiday pay, relocation allowances, loss of licence insurance and more.

She claimed that while Ryanair’s excuse for not engaging with the claim has changed over time, the reality is that the airline has never been prepared to deal with it.

They may not like it, she said, but that does not change the fact it is a pay proposal, she added.

She also claimed that Ryanair had repeatedly failed to furnish information requested from it by the union that was related to its pay proposal.

Ms Bolger also told the court that Fórsa had chosen to withdraw from the voluntary mediation process and as far as her clients were concerned, what they did was entirely justified and proper.

She said her clients are entitled to take industrial action whenever they want, as long as it is done within the confines of the 1990 Industrial Relations Act.

Ms Bolger also claimed the evidence provided in an affidavit from a union official cast aside a suggestion by Ryanair that the secret ballot that led to the industrial action was unlawful.

However, having read it, Mr Justice McDonald suggested that the affidavit did not provide sufficient evidence that the ballot had complied with the requirements of the 1990 Industrial Relations Act.

A rapid attempt was then made by Fórsa's legal team to get a supplemental affidavit from the union official addressing the gaps by a deadline of 3.50pm set by the judge, who said the hearing needed to end by 4.30pm in order to give him time to consider the case before giving his ruling.

The hearing was adjourned shortly after 4pm following the successful delivery of the affidavit.

Mr Justice McDonald said he would give his decision tomorrow morning as close to 10.30am as possible.

Earlier, the court heard that Ryanair claims a pay proposal submitted by Fórsa in March is covered by a 2018 agreement between the company and the union.

That agreement, negotiated after a series of pilot strikes at Ryanair last year, requires disputes to go through a mediation process before industrial action can be taken.

The airline claims that process has not yet reached a conclusion and as result, the union is not entitled to initiate industrial action.

It also alleges that the secret ballot of pilots held by Fórsa that gave rise to a vote for industrial action was unlawful and contrary to the union's own rules.

Continuing submissions on behalf of the company this morning, Martin Hayden SC said it was not Ryanair that had brought pay into the context of the mediation process set out by the 2018 agreement.

He said the application for its inclusion had been made at the insistence of the union.