Three young Afghanis, including a juvenile boy, were found inside a trailer after a motorist on a main Dublin road alerted the driver of a truck to banging from inside the container.
The driver pulled off the Nangor Road to nearby Park West in Clondalkin, west Dublin, and on hearing the banging rang gardaí.
When gardaí from nearby Ballyfermot Station arrived at 4.20pm on Monday and opened the trailer, they found three males inside.
The three individuals had documents appearing to show they were Afghan nationals.
According to the documents, one was aged 16, while the others were aged 20 and 22.
Gardaí said the truck had arrived off a ferry at Rosslare Port earlier on Monday.
The three were brought by gardaí back to Ballyfermot station, where they received a meal and a doctor was called.
Sources said there were “no visible injuries”.
An interpreter was also sought to assist gardaí and other authorities.
Tusla, the Child and Family Agency, was informed in relation to the care of the juvenile.
It is thought the three were brought to accommodation.
It is not yet known if any of them have claimed asylum.
It is understood the driver was not arrested but details were taken from him.
Gardaí will take statements from the Afghanis and try and trace their route.
A statement issued earlier by Garda HQ said gardaí in Clondalkin were investigating "possible immigration offences".
It said the truck arrived at Park West after coming into the country via Rosslare Port.
"When the driver opened truck, three men were located in the trailer," it said.
It said the trailer was taken away for technical examination.