"The reporting is done by the CCTV volunteers. However, they are in regular communication with the City Safe officers who are drawing their attention to more incidents," Mr Thomas said.
Liquor-ban breaches and disorder in the early hours of Saturdays and Sundays accounted for much of the spike.
Senior Sergeant John Fagan said CCTV helped officers "be in the right place at the right time".
"The volunteers are seeing things starting to brew, so we can get in there before an assault actually happens. They're getting really good at reading people's body language and seeing when people are squaring up for a fight."
Mr Fagan said the one-way-door policy, which meant patrons could not move between premises after 1am, had freed up police time.
Even a bar owner who was staunchly against the one-way-door policy before it was implemented said he had changed his mind. Overall the streets were "tidier and safer" than they were a year ago, said Des Wallace, owner of Bank St's Bacio bar.
"After 1am, I can focus on what I'm doing, not worrying about who is stumbling down the street, because they can't get in anyway."
Disorder on the streets was down to a small group of "less desirables". Some licensees could also do a better job of managing intoxication levels, he said.
"It's about realising that drunken behaviour is not tolerated. If you are going to turn up in a state then you won't be getting in."