According to ANP, this may result in labor actions in the Netherlands if talks with Ryanair stall.
Ryanair said it will cancel 24 flights on Friday during the second of three strikes planned by the pilots.
The pilots' union said that talks on Wednesday between the two sides did not lead to any "material change".
The Irish Airline Pilots' Association - which is part of the Fórsa trade union - is in dispute with Ryanair over pay and conditions.
Cabin crew have raised similar issues to Ryanir's Irish pilots in relation to seniority procedures for base transfers and promotions, but is also petitioning the carrier to stop forcing European cabin crew to set up Irish bank accounts.
Ryanair last night tweeted a letter it sent to Forsa, urging it to call off its third 24-hour stoppage scheduled for Tuesday.
Ryanair today announced cancellation of up to 400 flights with destination or departure from Spain on 25 and 26 July before strike convened by cabin Crew (TCP), which will leave ashore at least 50,000 passengers.
On 4 July, cabin crew from across Europe released a "Ryanair Crew Charter", with a list of 34 demands including "a fair living wage that reflects the work we do, predictable working hours, easier reporting sick process, and employment contracts in their own language, based on local rather than Irish law".
Most pilots flying for Ryanair are self-employed, which is why the airline is able to continue most flights. "These strikes are entirely unjustified and will achieve nothing other than to disrupt family holidays and benefit competitor airlines in Belgium, Portugal and Spain".
Ryanair said it "deeply regrets" the cancellations, due to action which it deems "unnecessary", and which will affect up to 50 flights a day to/from Portugal.