A European Arrest warrant has been issued for Gerard Hutch in connection with the attack on the Regency Hotel in February of 2016 during which a man was shot dead.
The High Court issued the warrant following an application from the Director of Public Prosecutions for the arrest of Mr Hutch, known as 'The Monk', who is wanted to face trial in Ireland.
Gardaí believe the 58-year-old has been moving between Spain, where he has a home, and other European countries.
His extradition was sought by the investigation team in Ballymun, which has been investigating the murder of Kinahan gang member David Byrne at the Regency for the past five years.
The 34-year-old member of the Kinahan organised crime group was shot dead at a boxing weigh-in by a gang of armed men dressed as gardaí.
Gardaí believe the attack was carried out by the Hutch gang in retaliation for the murder of Gary Hutch, the nephew of Gerard Hutch, in Spain in September 2015.
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Gardaí also believe the target of the Regency attack was Daniel Kinahan, who was identified in the High Court as a senior figure in organised crime and the controller and manager of the Kinahan gang, which the Special Criminal Court found is involved in international drugs and firearms trafficking and "execution style murders".
The murder of Mr Byrne escalated the ongoing feud between the two criminal organisations, which has so far cost 18 lives in Ireland and Spain.
Upon arrest, Mr Hutch can decide to contest his extradition in whatever country he is detained or waive that right and return voluntarily to Ireland to face trial.
Another nephew of Mr Hutch, Patrick Hutch Junior, walked free from the Special Criminal Court two years ago after his trial for the murder of Mr Byrne collapsed.
The 28-year-old had pleaded not guilty.
No one has been convicted of any offence in relation to the attack at the Regency.
Thirteen people have been convicted of murder in Ireland and Spain in relation to other feud murders, 32 others have been convicted in Ireland and the UK of other feud-related offences.