Brian Sherry, a former Garda Chief Inspector, made the claim ahead of the funeral of Eddie Hutch on Friday.
He said that the potential for the feud to spread beyond Dublin and the Republic of Ireland’s borders was very real.
“There are dissidents out there who are quite prepared to become involved in either side of this feud, if the price is right” he said.
“The difficulty that I would see is that this could actually spill over into the north.
“You could have dissidents from different factions becoming involved.”
Eddie Hutch, 59, was gunned down in north Dublin just three days after 32-year-old David Byrne was murdered at a boxing weigh-in event at the Regency Hotel on Friday 5 February.
The Continuity IRA initially appeared to claim responsibility for the Regency Hotel shooting but issued a statement afterwards to say that it had not been involved.
However, Gardaí have not ruled out the possibility that dissidents may have been part of the squad of six that carried out the hotel attack.
Forensic teams at the scene of Eddie Hutch's murder in Dublin.
The shootings are primarily believed to be linked to a feud between two rival families, the Kinahans and the Hutches, with drugs at the heart of the turf war.
It’s believed that dispute began when members of an international drugs cartel allegedly led by Christy Kinahan fell out.
The result was the murder of Gary Hutch in Marbella last year.
Gary Hutch was accused of being an informer and of double-crossing the Kinahans, and his uncle Gerry ‘The Monk’ Hutch was then threatened by Christy Kinahan’s son Daniel.
It’s believed that Daniel had been the target in the Regency Hotel shootings, where men armed with AK-47s stormed the boxing weigh-in, shooting three people, including the deceased David Byrne.
In retaliation, Eddie Hutch, a ‘soft target’, was murdered to send a message to the Hutch family.
Jim Guerin, whose sister Veronica was murdered in north Dublin almost 20 years ago for being the first journalist to expose the drug lords, said the situation has deteriorated since then.
He said that the body set up in the wake of Veronica’s death, the Criminal Assets Bureau (CAB), has been largely bypassed by the criminals.
“I think it’s got a lot worse and that’s a terrible pity,” he said.
“We’ve got a lot more gangs, they have a lot more guns and firepower.
“What’s happened now is that the criminal gangs have become aware of the modus operandi of the CAB, and therefore they put their assets offshore or money might never come into the country.
“The amount of resources that’s available to the criminals compared to the amount that’s available for the Garda has made it a most unfair match.”
Mr Sherry said that the availability of dissident weapons could see the violence spiral.
“These people are very heavily armed and they don’t appear to have any respect or fear of the law,” said Mr Sherry.
“This could spill over and you could have innocent people getting hurt in this gang warfare.”
Former Garda Chief Inspector Brian Sherry
“The introduction of AK-47s, which are generally a paramilitary type weapon, is a new dimension and that is very, very worrying.”
Sean Donohoe and Ciaron Kearney are former heroin addicts that spent almost 40 years in jail between them.
They were also heavily involved in the drugs trade in Dublin, but have since turned their lives around and now work with the Lighthouse Drop-In Centre in Dublin in an attempt to help others.
“My worst was when I was sleeping with guns under my pillow every night, paranoid that people were going to come through my door and shoot me,” said Mr Donohoe.
“There was no room for a guilty conscience when I was living that life.”
Ciaron Kearney said that he used to be a big player within the drugs scene in Dublin and said that toughness was needed.
“I was dangerous, if I was approached the wrong way,” he said.
“That’s how everyone survives when you’re out there, it’s either be bullied or be a bully.”
Mr Donohoe said that although Garda had upped their presence on the streets, he remained sceptical as to whether it would have an impact.
“Dublin will always have gangs,” he said.
“There’ll always be drugs and there’ll always be shootings.
“That’s just the truth of it, you will never stop the gangs in Dublin.”
A heavily armed response unit of around 55 Garda have supplemented ordinary officers on the street, with 24-hour checkpoints still in place across the city.
Dublin is holding its breath as it waits to see if further violence is to come in what has become an increasingly bitter and bloody feud.