The man was arrested on Friday and remains in custody.
An Garda Síochána have arrested a 23-year-old man on foot of an European Arrest Warrant issued by Essex Police, in relation to the Essex people smuggling tragedy.
Eamon Harrison, of Mayobridge, Down is charged with 39 offences of manslaughter, as well as human trafficking and immigration offences.
He has appeared before the High Court, Criminal Courts of Justice, Dublin and has been remanded in custody.
Gardaí said he continues to be remanded in custody from the District Court in respect of an offence in this jurisdiction.
An Garda Siochana continues to assist Essex Police in this investigation.
The PSNI have also urged brothers Ronan and Christopher Hughes to come forward and hand themselves in to police in Northern Ireland.
Ronan Hughes, 40, and his brother Christopher Hughes, 34, from Armagh, Northern Ireland, are wanted on suspicion of manslaughter and human trafficking in connection with the deaths of 39 people, whose bodies were found in a container in Grays last week.
Speaking in a press conference at Police Service of Northern Ireland Headquarters on Friday in Belfast, Senior Investigating Officer Detective Chief Inspector Daniel Stoten said: "Today I want to make a direct appeal. Ronan and Christopher hand yourself in to police. We need you both to come forward and assist us with this investigation."
