The eight stowaways found dead in a freight container in Co Wexford at the weekend travelled to Ireland by mistake, according to garda∅ investigating the tragedy.
They had intended to travel to a UK port, the Garda National Immigration Bureau said last night.
Gardai found UK telephone contact numbers in the freight container, which arrived in Ireland from the Belgian port of Zeebrugge last Thursday.
"We have no doubt but that they were intending to go to the UK. There is nothing to indicate that they had any intention of coming here," said one garda.
Garda∅ say the asylum-seekers are likely to have cut their way into the metal container at Zeebrugge, believing it would make a half-day journey to a UK port.
Instead, the container, loaded with office furniture for a computer firm in Wexford, embarked on a two and a half-day journey to Belview port near Waterford.
Conditions in the sealed P&O Ferrymasters container in the hold of the vessel would have been cold and dark with little air.
The vessel encountered a force 10 gale as it headed for the English Channel.
After docking at Belview Port, the container was transported to Wexford Business Park at Drinagh where it was opened on Saturday morning.
The five survivors, three men, a woman and a teenage boy, remain in Wexford General Hospital where their conditions improved yesterday.
Two were described last night as "fairly seriously ill".
Three of the five - a man, a 40-year-old woman and the teenage boy - remained in intensive care yesterday, while another man was being treated in the coronary care unit.
The deceased were three adult males and one female as well as three boys aged four, nine, 17 and a 10-year-old girl. Post mortems were being carried out last night.
Gardai confirmed that six of the group were Turkish nationals and representatives of the Turkish embassy arrived in Wexford last night to help investigations. Meanwhile, the Waterford shipping company, C2C Shipping Lines, which transported the 13 stowaways is to step up security checks as a result of the tragedy.
Garda∅ believe the stowaways were assisted by criminals who severed the metal security seal in the container and then resealed it with silicone gel once the passengers were on board.
The tragedy prompted the Taoiseach to call for further co-operation between European countries to combat human trafficking.
He pledged the State would "spare no effort" in bringing those responsible to justice.
The Minister for Justice, Equality and Law Reform, Mr O'Donoghue, described the deaths as his "worst fear" but said as long as there was money to be made from trafficking, there would be criminals ready to arrange transport.
The incident comes ahead of a meeting of EU leaders in Belgium next weekend which will consider a proposed European arrest warrant to cover offences including the smuggling and trafficking of people.
EU justice ministers failed to approve the warrant's introduction last week after Italy insisted that the list of offences should be reduced.
Government sources said last night the Taoiseach, Mr Ahern, may telephone the Itallian Prime Minister, Mr Silvio Berlusconi, to press the issue with him.
The deputy leader of the Labour Party, Mr Brendan Howlin, said the State needed a "much more developed system" to cater for economic migration.
The Wexford TD said a "rational response" to the problem was needed at EU level, with each member state doing its share. What was needed was a quota of economic migrants across the EU so that "people can have some formal way of applying for that, and then genuine refugees can be dealt with separately".
The Bishop of Ferns, Dr Brendan Comiskey, said he agreed with the Taoiseach that human traffickers should be "sought out and punished".
But to target traffickers alone was "wholly inadequate" and we needed to move beyond that.
Mr Peter O'Mahony, from the Irish Refugee Council, said people would "continue to allow themselves to be smuggled or will fall into the hands of traffickers if Europe continues to be as impenetrable to many as it is".