Dublin Airport has advised passengers to expect queues for security screening over the coming days and weeks due to staffing issues.
There have been reports on social media of lengthy delays getting though security in Terminal 1 and Terminal 2 over the weekend.
One of woman told RTÉ News that she was queuing for more than an hour.
Another man highlighted on social media that he was delayed for two-and-a-half hours, and missed his flight as a result.
The daa, which operates Dublin Airport, said "some passengers are experiencing delays" this weekend and it has apologised to affected people.
"Like other airports all over Europe, we are currently working extremely hard to ramp-up our operation at Dublin Airport after the collapse of international travel over the past two years including the hiring and training of staff after 1,000 workers left the airport under a voluntary severance scheme during the Covid-19 pandemic," it said.
Since the start of the year, over 100 new security staff have been recruited.
However, the daa said the recruitment, training and background security checks for all staff working at international airports takes a number of weeks.
"This is having an impact on the length of time it is taking passengers to get through security, particularly at busy times," it added.
"We apologise in advance but queues for security are likely to be experienced at peak hours over the days and weeks ahead as we continue to bring trained staff on board."
Mobile phone footage from inside Terminal 1 showed long queues at around 6pm this evening, meandering through the length of the departures area. The queues have since eased.
Bottled water was being made available to the people queuing for security.
With further delays expected at peak hours over the days and weeks ahead, the daa has urged passengers to allow plenty of time ahead of their flight.
"To minimise the impact, we encourage all passengers to check-in bags where they can and to carry the minimum amount with them when presenting at security."
Intending passengers are also encouraged to "be at the airport a minimum of two hours before boarding a short-haul flight and three hours prior to boarding a long-haul flight."
The daa has acknowledged that some people have missed flights due to the delays.
In a statement it said "we empathise completely with any passengers who have missed a flight this weekend as a result of the delays at airport security."
"Thankfully, many of those passengers have been accommodated on later flights or have rebooked," the daa said.