Dublin Airport operator daa has said the number of passengers travelling through the airport "will increase over the coming days" as the Easter weekend approaches.
In a statement, daa said it would continue to "refine and adapt its security screening operation, to ensure that all passengers can pass through security in plenty of time to make their flights".
It comes as passengers were asked to queue outside Dublin Airport terminal buildings this morning.
Videos posted on social media showed a queue of waiting passengers stretching from the doors of Terminal 1 down the exit ramp.
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This morning, daa said on Twitter: "Passengers were heeding our advice from very early this morning to arrive at the airport up to three-and-a-half hours before their departure time.
"This resulted in us having to stagger the flow of passengers into the terminals which was well managed by Airport Police."
It said the queues were moving and thanked passengers for their "cooperation and patience at this extremely busy time of the morning in advance of the first wave of departures".
Several passengers also took to social media to post about their experiences travelling through the airport.
While some described it as "madness" and "chaos", others praised the airport and staff for how they managed the situation.
This morning passengers were asked to queue outside @DublinAirport T1 &T2. daa said it was "filtering passengers… in an orderly manner to join check in and security queues which are moving" @rtenews https://t.co/dS6714KQId— Laura Fletcher (@fletchl) April 9, 2022
One experience shared on Twitter was that "queues are moving, staff are pleasant and doing their best given the circumstances".
Another person wrote that the "huge queues (were) moving quickly", and another passenger said: "Very busy but through in 45 minutes."
Meanwhile, Ryanair CEO Michael O'Leary has reiterated his call for the Defence Forces to be brought in to help ease queues at the airport.
He told RTÉ's The Business: "The army have the most expertise in security, they are the best in Europe at it and I think the European Union would accept that and it would solve the problem.
"It is a little bit more difficult to recruit airport staff at the moment because they have to have more specific security clearance so [Dublin Airport] is short about 200 staff.
"They think they will be able to recruit these over the next two months, but April and May is going to continue to be problematic."
Mr O'Leary said the era of cheap flights is "not coming to an end" and that aviation was important to an island economy like Ireland.