Lawyers for a Northern Ireland man wanted in connection with the discovery of the bodies of 39 people in a trailer in Essex in October have told the High Court they have a number of issues they are unhappy about in relation to a warrant seeking his surrender to the UK.
Truck driver Eamon Harrison, from Mayobridge, Co Down, is being sought by British authorities, but is challenging an extradition request from the UK.
It is alleged that the 23-year-old delivered the trailer in which the Vietnamese migrants were found to the Belgian port of Zeebrugge for onward transportation to the UK.
Mr Harrison is facing 39 charges of manslaughter.
He is also accused of conspiracy to commit human trafficking and conspiracy to assist unlawful immigration.
He was arrested by gardaí from the extradition unit last month on foot of a European Arrest Warrant.
The High Court has been seeking additional information from British authorities in relation to the warrant, which refers to Mr Harrison as a British citizen.
Counsel for the defendant, Siobhan Stack, said that "practically all" of the details in the warrant had been provided by the UK Crown Prosecution Service, rather than the issuing judicial authority.
The court was previously told that Mr Harrison had been travelling on an Irish passport at the time the alleged offences occurred.
His legal team has raised detailed points of objection to his surrender to the UK.
His lawyers argued that Mr Harrison's nationality was critical in determining whether his surrender to British authorities was prohibited on grounds of extra-territoriality.
They also said the warrant itself was lacking information and was "perhaps rushed".