The men were stopped at Dublin Airport on Monday
Three men will appear in court later after an alleged human-trafficking operation was detected at Dublin Airport.
The three - aged 28, 56 and 61 - are currently being held at Ballymun, Swords and Coolock garda stations.
Two of the group are Aer Lingus staff members.
Gardaí say they will appear before Dublin District Court, charged in connection with immigration offences.
A foreign national from outside the European Union arrived at Dublin Airport on Sunday night, and gardaí followed indications that two Aer Lingus staff were going to help get the man past immigration controls.
The garda operation also involved searches of property and vehicles.
Gardaí are trying to establish how many times this may have happened before.
Security analyst Declan Power told Newstalk Breakfast that the airport needs to have regular audits by external experts to find the holes in their system.
"They were looking for weak points within staff on the airport.
"The concourse of the airport is Dublin Aviation Authority's responsibility - so it behooves both organisations to up their game here a little bit."
"One key thing that we should learn out this, particularly in this country, we can have the best security system in the world and things are going to shift and change.
"Unless you're auditing it regularly, unless you're testing it regularly, unless you're doing in what's known in military terms as red teaming - they probably do do regular audits, to give them credit where credit is due, but it's probably done in house and it's probably become a box-ticking exercise.
"When you have a red teaming exercise you have a team of people who no skin the game with the company, they're hired to come in, to do a walk around first some months beforehand and assess what they feel are the weak points and then they put together a scenario and penetrate it and find all the holes".