Fianna Fáil's Transport Spokesperson Robert Troy is calling on the airline to provide clarity to all customers that could be affected by the disruption to services.
But he says they have only been given details of the cancellations up to Wednesday of this week so are "in the dark" after that.
Deputy Troy says customers need to know where they stand.
Chief Executive Michael O'Leary promised the problem would not recur in 2018 but said there would be a "large reputational impact" from the cancellations. The disruption stemmed from Ryanair scheduling too many pilots for vacation.More news: American tourists attacked with acid in Marseille's train station, prosecutor says
Ryanair will offer refunds or alternative flights to customers affected by the cancellations.
Rory Boland, travel editor of consumer group Which?, said it is "essential" that Ryanair releases a full list of flights that will be affected to give passengers "as much time as possible to make alternate arrangements". "We will try to do better in future", he said.
He was at pains to add that the airline will not contest this compensation, saying: "When we make a mess in Ryanair, we come out with our hands up".
The airline said that less than two percent of its flights are affected by the cancelations.
Robin Kiely, head of communications at Ryanair, said: "We have operated a record schedule during the peak summer months of July and August but must now allocate annual leave to pilots and cabin crew in September and October".More news: Cowboys have highest value in National Football League , according to Forbes
None have been cancelled on Wednesday but no details have been published for Thursday onwards.
Asked if he believed he should lose his job, Mr O'Leary replied: "No, I don't think my head should roll, I need to stay here and fix this". Ryanair said that it will release a full list of canceled flights (through the end of October) by Tuesday.
A Reuters reporter, whose flight from Dublin to Barcelona on Sept. 18 was cancelled on Friday, was offered a choice of a surcharge of 250 euros to take an earlier flight on Sept. 18 or 60 euros to take a flight on Sept. 19.
If not, they would be moved to flights the day before or the day after and the airline would meet its obligations over compensation.
"If they're not satisfied they can have a full refund and will be eligible for the EU261 compensation".More news: How to watch Premier League football online
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