The Passport Office has called up extra staff to deal with an average 4,500 applications a day in the holiday rush.
About 33,000 passport applications by holiday-makers are waiting to be processed.
An extra 128 temporary staff have been employed across Irish passport offices at Molesworth Street, Balbriggan, Cork and London this summer.
Over the next 10 days the Passport Service expects it will process just under 23,000 Passport Express applications, the Department of Foreign Affairs told the Herald.
"The remaining are a mixture of urgent counter applications, postal applications, applications from Northern Ireland and applications from our missions around the world," a spokeswoman said. She urged people to check that their passports are in date before they book holidays, and recommended that people use the Passport Express Service.
"All correctly completed applications submitted through the Passport Express service, used by the vast majority of passport applicants within the State, are being processed within 10 days."
"The Passport Service strongly recommends citizens check the validity of their passport now and apply or renew it in advance of making any travel bookings.
"The Passport Express service, with the guaranteed 10-day turnaround, is the recommended channel for making a passport application."
She said while counter applications can be processed within three days, holiday makers are recommended to apply early.
"Applicants should note that if absolutely necessary, the fastest turnaround time for passport applications is three working days, and then only at the public counters in Molesworth Street and Cork. Accordingly citizens are recommended to apply early."
She said that the numbers waiting on their passports this year reflected a typical summer period.
Last year, an extra 50 temporary clerical officers were hired to deal with a backlog of passport applications which were coming in at a rate of 6,000 per day during the peak.