Airports in Dublin and Belfast will see route cuts involving a number of airlines in the next few months.
Cathay Pacific is to suspend its Dublin to Hong Kong service, which operates four days a week, between 7 November this year until 29 March next year.
The airline said this was "a difficult decision to make, but also a necessary one in view of the commercial challenges we currently face".
It said the service would resume in late March 2020, while it remained confident of the "long-term prospect and strength of the traffic between Ireland, Hong Kong and the rest of Asia".
Meanwhile, Aer Lingus is to end its summer services connecting Belfast City Airport to Faro and Malaga.
Aer Lingus said the decision came "following a commercial review which determined that the routes were not performing in line with expectations".
It said it would continue to delivery its high frequency, daily service between Belfast City and London Heathrow next year.
The Fórsa union, which represents staff at the airline, has criticised what it says is Aer Lingus' failure to consult or communicate with workers at the airline's Belfast base.
"Aer Lingus staff in Belfast are very angry and worried about their future, and the future of routes in and out of Belfast," said Fórsa official Ashley Connolly, who added that Aer Lingus staff based in Belfast only became aware of the decision following media reports this morning.
"The company's failure to engage with their own staff, to keep them informed of decisions that affect their livelihood, damages the credibility of the airline."
Meanwhile, UK media reports also suggest that Ryanair is ending services between Belfast International Airport and Berlin, Manchester and Lanzarote.
This follows cuts to Ryanair services between Belfast International and a number of Polish airports.