The 16 people who were found in a container in Rosslare, Co Wexford are understood to have been transferred to an immigration centre in Dublin.
All 16 who were in the container on the ferry which originated in Cherbourg, are understood to be men aged between 20 and 40.
Last night they were transferred to the capital following a medical assessment.
And sources said they may have had a hellish 30-day trek across Europe before reaching our shores.
The alarm was raised by a staff member carrying out a routine inspection on the car deck when she heard banging noises from inside the refrigerated container.
Shocked Stena Line crew members then found 16 men huddled together within the trailer at 9.20am before bringing them to safety.
Staff alerted gardai 25 minutes later and took the men, from Iraq, Iran and Romania, to a private passenger lounge and offered them food, drinks and blankets.
Officers were last night probing how they ended up on board.
Councillor and paramedic Ger Carthy, who spoke to the migrants, said there was huge relief a major catastrophe was averted.
He added: “This could have been a lot more tragic and that’s something we don’t want on our shores. We’re extremely lucky the crew member figured out they were in there after hearing noise at the side of the trailer.
“I’d say the migrants are relieved they’ll end up getting asylum here.”
Gardai said immigration officers are processing the men and are trying to find out if one of them is a juvenile.
A spokesman said: “After our initial inquiries they will transferred to a reception centre organised by the Reception and Integration Agency (RIA) where they will be provided for all their welfare concerns.
“This has been a traumatic experience for these men and they are being treated with sympathy and compassion.
“The articulated lorry was photographed and examined on the ferry and has now been removed to a secure location for further technical examination.
“The articulated lorry (tractor and trailer) are owned by a local, Irish-based company. The owners are co-operating fully with the ongoing investigation.
“The driver is a male in his 50s, resident of Ireland for over 25 years and he is co-operating fully with the ongoing investigation.”
