Dublin Airport said its operations will be challenging for the coming week as it tries to "ramp back up" staffing levels following the pandemic.
The warning comes as queues of up to 90 minutes to get through security screening in Dublin Airport were reported by passengers this evening.
Some passengers travelling through Dublin Airport last week during the bank holidays also reported long waiting times at security.
Kevin Cullinane, daa Group Head of Communications, said around 100 new staff have been recruited since the start of the year but that there have been delays in bringing some of these people into operation because of the requirement for enhanced background checks for aviation workers that came into effect on 1 January.
He said the "logjam" that was causing delays has now been removed and daa hopes that more new staff can begin working in the coming weeks.
Around 1,000 staff left Dublin Airport in a redundancy programme during the pandemic and while there has been recruitment to replace staff in certain areas as passenger numbers begin to return to pre-pandemic level, Mr Cullinane said "it's not as simple as flicking a switch".
Passenger numbers, he said, are now at about 75% of 2019 levels but while they try to ramp back up their operations they are appealing to passengers to arrive at the airport at least two hours before a short haul flight and three hours before travelling long haul.
Mr Cullinane also said that passengers can also help to prevent delays at security by reminding themselves of the security restrictions before they travel and to be prepared for the checks as they enter the security screening area.
He said that airline summer schedules will begin in just over a week's time and the airport will get busier but that operations will remain a challenge for some weeks as staff are recruited, vetted and trained.
The issue, he said, was not unique to Dublin and added that airports around Europe are experiencing similar operational issues as international travel returns towards pre-pandemic levels.
