Aer Lingus has announced plans to cut up to 20% of flights over a five-day period next week amid industrial action.

Pilots at Aer Lingus served notice to the airline of their intention to launch an indefinite work-to-rule from next Wednesday, in a move branded as “insidious” by the company.

It comes after the Irish Airline Pilots’ Association (Ialpa) voted overwhelmingly for industrial action in a dispute over pay earlier this week.

From next Wednesday, Ialpa members at the airline will not do any overtime or out-of-hours duties.

The pilots are seeking a pay increase of 24%, which they say equates to inflation since the last pay rise in 2019.

Aer Lingus has described the industrial action as “entirely unnecessary” and warned that it will result in significant disruption to customers.

It has also characterised the pay demand as unrealistic.

Aer Lingus has warned the indefinite work-to-rule action will have a “cumulative and negative impact” on customers, including flight cancellations close to the time of travel.

In a statement, the airline said: “In order to protect as many services as possible from the impact of the industrial action, Aer Lingus has to take the step of cancelling between 10% and 20% of our flights on the first five days of the industrial action – Wednesday 26 to Sunday 30 June.

“These cancellations will be implemented over the course of the next two days. Implementing these cancellations is to enable us to protect as many services as possible for as many of our customers as possible.”

In addition, Aer Lingus on Thursday announced that it will be offering a number of options to customers who may be affected by planned industrial action by Ialpa.

Customers will be given the option to change their flights for free or cancel their flight and claim a refund or voucher.

Aer Lingus said the Ialpa action comes at “peak holiday season for families”.

The airline said: “We will do everything we can to minimise the impact for customers.

“However, it is inevitable that there will be disruption as a result of this industrial action, and we will communicate any changes, delays or cancellations to impacted customers as soon as possible.

“Where there are cancellations, we will look to reaccommodate customers as quickly as possible and will work with other airlines, with partner airlines and seek to hire in aircraft for this purpose.”

Earlier, Irish premier Simon Harris said it is “utterly reprehensible” that children are being “used as pawns” in the industrial relations dispute.

Mr Harris urged the airline and the pilots to “sort this out”, noting that the matter had been considered by State workplace relations institutions.

Speaking on Thursday, Mr Harris said: “Many, many, many families across the country have seen parents and others go out to work over the course of the year and set aside a few bob to try and take their kids on a family holiday.

“And the idea that passengers – children due to go on their summer holiday – would be used as pawns in an industrial relations dispute that has already been considered by the Labour Court is utterly reprehensible, and people need to step back from the brink.”

Asked about what Government could do in the dispute, Mr Harris said it already provided the State’s industrial relations mechanisms.

He added: “I would absolutely encourage people to utilise them.

“And let me tell you this, people have a right to engage in industrial disputes but I think anybody who engages in an industrial relations dispute and does not use those mechanisms, I don’t imagine they’re going to get much gratitude or support from the people of Ireland, the parents of Ireland, trying to pack bags and bring their kids on holiday, not sure whether that’ll now be able to go ahead.

“So, get back in a room and sort this out is my very clear message.”