Dublin Airport says there were significant queues in both terminals in the early hours of this morning, in particular between 2.30 and 4.30am.
It says at the peak, it took some passengers 70 minutes to pass through security.
Dublin Airport says it was "mainly the result of a large number of passengers arriving earlier than expected ahead of flights later in the morning".
DAA says the shortage of security screening staff is the key contributory factor to the current difficulties.
It invited around 250 candidates for an interview this week, and made job offers to 100 of those.
