Gardaí and the Department of the Marine are investigating the circumstances under which 13 eastern Europeans had to be rescued from an island off Skerries in north county Dublin at the weekend.
The rescue happened at around 10pm on Saturday night after the coastguard received a call from a member of the public.
It is believed that the 13, thought to be mostly Latvian, were on the island working as periwinkle pickers.
Rescuers were led to believe that the group were put on the island by boat earlier in the day by their employer.
The island, known as Colt Island, is an uninhabited exposed landmass a quarter of a mile off the town of Skerries.
Having completed their work they were due to be picked up again later that evening.
However, it is believed they received a phone call on Saturday evening saying that the boat which was due to pick them up was experiencing engine trouble and that they would have to stay on the island for the night.
Rescuers believe that one of the stranded party managed to get a message to a friend on the mainland who subsequently raised the alarm.
The RNLI Lifeboat from Skerries was launched and went to the island. There it found the group huddled around a small camp fire. It is understood they were not wearing any kind of protective clothing. The group were then brought ashore.
Gardaí in Skerries have launched an investigation into the matter.
They are trying to establish who was responsible for putting this group onto the island and the circumstances under which they were left there.
Separately, the Department of the Marine says it is enquiring into whether the boat owner was licensed to be carrying out such work.
Meanwhile, SIPTU has called for a thorough investigation into the incident.
The union has said urgent action must be taken to prevent another tragedy like that at Morecambe Bay in England taking place.
SIPTU's Anton McCabe said it appears that this was another example of migrant workers being used as a cheap commodity.
