Garda chief to meet concert promoter MCD – Justice Minister
Mr Shatter said what happened at the concert in the Phoenix Park was "very unusual".
He said the Garda Commissioner was looking into the events that occurred.
"I think there are issues for the promoter of this event to clarify," he said.
Mr Shatter said he had to be careful about what he said as an individual was going to be before the courts.
Gardai are hunting a number of people after a spate of attacks at an outdoor concert left at least nine people wounded -- two of them seriously.
A man in his early 20s died after a suspected drugs overdose at the concert.
Gardai said they received reports of a "significant number" of random unprovoked attacks at the show.
Last night officers said they believed other people may have been injured in the spate of attacks, which happened between 8.30pm and 1am.
They said that a number of people who may have received minor injuries might not have sought immediate treatment or reported the incidents. They asked these people to come forward to help them with their inquiries.
Concert promoter MCD said that it had taken "every precaution as far as possible" to ensure safety at the concert, but added "there's only so much one can do".
Gardai have asked witnesses to any of the attacks to come forward and are also examining CCTV footage in an attempt to identify other attackers.
It is understood that a glass bottle was used in at least one of the assaults and that knives were also used, but gardai were continuing to work to establish full details last night.
Three of the stabbing victims remained in Connolly Hospital in Blanchardstown yesterday for treatment while two of them were in a serious but stable condition.
The sister of one of the men, who did not wish to be named, said that her 25-year-old brother was stabbed four times in the back and suffered a collapsed lung.
He received attention at the medical tent and on returning home his sister, a nurse, suggested he go to hospital straight away.
"He collapsed when the ambulance arrived," she told the Irish Independent.
"He was just watching the show when someone came up and stabbed him four times in the back. He didn't know the guy.
"He can hardly remember it. He said it was all a blur," she said. "Two other guys who are on his football team were also attacked but he wasn't at the concert with them."
Serious questions have been raised about the security at the concert and how anybody could get a knife into the venue.
MCD managing director Denis Desmond condemned the violence yesterday.
He said the behaviour was not reflective of the " vast majority" of the 45,000 fans who he said were "extremely well-behaved and should be congratulated".
Mr Desmond said that public safety was the number one priority and that security and gardai numbers were in excess of the required numbers for a licensed event of the size.
"Ticket holders entering the site were subject to a search permissible by law.
"Every precaution, as far as possible, was taken to ensure the safety and security of the audience at all times.
"Despite our best efforts. . . there is only so much one can do to combat anti-social behaviour," he said.
The man who died became ill before Swedish House Mafia took to the stage and came to the medical tent for help at around 7pm, but later died in hospital.
Gardai have been working to identify him.
Mr Desmond said that he was extremely shocked and saddened to hear about the death and urged people to help gardai with their inquiries.
Two other men, one from Ronanstown, Co Dublin, and other in Clonee, Co Meath, also died from suspected drug overdoses, but it is unclear if they attended the concert.
Both died in the early hours of yesterday morning.