Speaking after a meeting with Garda Commissioner Nóirín O’Sullivan and her senior officers, Ms Fitzgerald said they would “stand down this threat”.
She announced an extra €5m, which, she claimed, would provide “saturation policing” in the city.
The minister said the funding would also allow for 24-hour armed patrols, which will be the forerunner to a dedicated Regional Support Unit for the city.
This unit, which had already been decided upon, would have a staff of 55 once fully up and running.
Addressing the media on the back of Monday night’s murder of Eddie Hutch in suspected revenge for the shooting dead last Friday of David Byrne at the Regency Hotel in Dublin, Ms Fitzgerald said the killings showed a “wanton disregard for human life”.
On the military assault at the hotel, in which three men wore elite Garda-type uniforms and each brandished AK-47s, she said: “This is unprecedented in terms of effrontery, for a criminal gang to go into a hotel, with families, with the kind of armoury that they had and the way they were dressed.”
She said the city was now in the grip of a gang feud: “We have a cycle of revenge and retaliation. The gardaí, with their intelligence and security units, will do everything to prevent a further loss of life, to interrupt this cycle.
“We will stand down this threat from these gangs and the gardaí will have every resource that they need in order to have the kind of saturation policing that we need to see ... on our road networks and in our communities.”
She accepted once feuds like this start it is very hard to put a lid on them. “These gangs are relentless, as we’ve seen in various criminal feuds in the past, but let’s not make the assumption that they’re unstoppable, let’s just say they’re relentless. These people are not above the law.”
She cited the success of gardaí in Limerick in 2009 and the “saturation policing” there, with 24 of the 25 gangland murders being solved. Asked how that kind of policing can be provided, with just 12,800 gardaí, as opposed to almost 14,500 in 2009, she replied: “The Garda commissioner has assured me that given the support of government that kind of patrolling necessary, and the armed unit can be put in place, actually is being right now.”
The minister accepted that you cannot have the kinds of staffing cuts — as happened since 2010 after the economic crash — without “consequences” for the force.
She said gardaí “put their lives at risk” in confronting these gangs and said gangland murders had dropped from a height of 22 in 2010 to three last year.
She said reports from the Regency Hotel manager that three 999 calls went unanswered would be investigated. However, she said the first garda car was dispatched to the hotel within minute and all units within five minutes.