A 23-year-old Northern Ireland man has been arrested in connection with the investigation into the deaths of 39 migrants who were found dead in a lorry container in Essex last month.
He was detained by police in the early hours of Friday and was questioned on suspicion of conspiracy to traffic people and conspiracy to assist unlawful immigration.
The people found dead, who were from Vietnam, were eight women and 31 men. Ten teenagers, including two 15-year-old boys, were among the victims.
Lorry driver Mo Robinson (25) has been charged with 39 counts of manslaughter. Three other people who were arrested on suspicion of manslaughter and conspiracy to traffic people have been released on bail.
The development comes as the Republic's Justice Minister Charlie Flanagan called for security to be tightened at all ports in Ireland following the discovery of 16 people in a container on board a ferry bound for Rosslare.
Mr Flanagan he is to meet with Garda Commissioner Drew Harris to see how "best to ensure that this type of incident is dealt with in accordance with the law", RTÉ has reported.
Fourteen adult males and two juvenile males were discovered in a container on board a Cherbourg to Rosslare ferry on Wednesday.
They are believed to be of Kurdish origin from Iran and Iraq.
The men have claimed asylum in Ireland and are being processed under immigration legislation by gardaí and members of the National Immigration Bureau.
Mr Flanagan said his department is working with European colleagues, and he hopes to ensure that there is "sufficient security to combat the scourge of human trafficking".
Fianna Fáil's justice spokesperson Jim O'Callaghan said that people need to be protected from traffickers and smugglers, and that it was "purely fortuitous" that the 16 people survived the crossing from France to Rosslare.
