Justice Minister Alan Shatter has said he regrets the Collins family have given up a life of 24-hour armed Garda protection for relocation outside Ireland.
Publican Steve Collins and his wife and children have been under constant threat of attack from the McCarthy-Dundon gang in Limerick city after testifying against crime boss Wayne Dundon.
The family run pub, the Steering Wheel in Roxboro, was shut last week after being bought by the State in one of a series of moves to create a new life for the family.
Mr Shatter said he has been determined to ensure the Government did everything it could for them.
"Mr Collins and his family stood by the institutions of this State and paid a dreadful price for the courage which they showed. It is vital that the State is seen to stand by them," he said.
"Despite the great progress which the gardaí have made in tackling the gangs in Limerick - to which I pay tribute - it remained necessary for Mr Collins and members of his family to have intensive Garda protection."
It is understood the family will all keep their identities.
The Collins family have been targets of the McCarthy-Dundon outfit since December 19 2004 when adopted son Ryan-Lee refused to serve the 14-year-old sister of Wayne Dundon at the family's pub, Brannigan's.
Dundon threatened that night to shoot the then 18-year-old barman and hours later a gunman shot him twice in the legs.
In April 2009, Roy Collins, the eldest son, was shot dead in the Steering Wheel prompting a huge crackdown on gangs in Limerick and calls for tougher laws to thwart organised crime.
It is understood plans for the secret relocation have been under way for well over a year with Mr Collins making the final decision that the family's future is best served living abroad.
"While, for security reasons, I cannot go into any details, I can say that the State has offered and is giving him every assistance possible in giving effect to that decision," Mr Shatter said.
"Of course, I regret that Mr Collins had to take this decision but I fully understand it and I am sure all right thinking people will wish him and his family well in their move.
"The greatest tribute which can be paid to their courage is for the gardaí to continue to bring to justice those involved in gangland activities in Limerick and elsewhere and I know they are determined to do just that. They have my full support and that of the Government in doing so."
Mr Collins and family members have been protected 24 hours a day by a team of elite armed gardaí and plain clothes officers for the last three years.
They flew out of Shannon Airport yesterday to a new life.
The McCarthy-Dundon outfit is under investigation for a series of gangland murders including the killings of Roy Collins and Garryowen rugby player Shane Geogheghan.
Gang member Ger Dundon's former partner is now a State witness. April Collins, no relation to the exiled family, was central to the prosecution of John and Wayne Dundon earlier this year for making threats against members of her family.