KEY POINTS:
Today's tightening of rules around access of young people to alcohol comes after a number of high profile incidents in recent years. We look at some of the worst events
August 2007, Dunedin
Rioting after the Undie 500 event led to almost 70 arrests, mainly of students, in Dunedin.
Police were pelted with bottles, drunken students set fire to cars and mattresses.
The rioting was centred in the heart of the student area of North Dunedin.
Police said they were at one of the flats talking to the occupants when they began to be pelted with bottles. "It was totally unprovoked," police said.
It took police, with extra reinforcements from outlying areas, until about 11pm to bring the crowd under control.
But some students claim the police provoked the riot.
January 2006, Mt Maunganui
Police faced drunken violence and abuse for the second weekend running when they were called to an out-of-control Mt Maunganui party early on a Saturday morning.
No injuries were suffered by the dozen unarmed officers or 60 partygoers but six women and two men were charged with issues including disorderly behaviour likely to cause violence and resisting arrest.
The booze-fuelled fracas came a week after a policewoman responding to a riot at a 21st birthday party at Welcome Bay was left in critical condition after she was allegedly hit with a metal wheel rim.
Four policemen also received minor injuries.
New Year's Eve 2006, Rotorua
Police made 41 arrests, up eight on New Year's Eve 2005. A group of young people, many of whom had gang associations, gathered near the carnival area at the Rotorua Lakefront, intending to have a confrontation.
Shortly after midnight police broke up a fight involving more than 20. Most of the arrests were for breaching the liquor ban but some were for disorderly behaviour.
New Year's Eve 2005, Wanaka
About 500 drunken youths rioted at a campsite, throwing bottles and punches at police and firefighters.
The mayhem at the Albert Town campsite, in which a car was set alight, left one police officer injured and police cars damaged.
The disorder began when a group of youths rolled over the car and hurled a petrol bomb at it. Firefighters extinguished the blaze.
Police arrived soon after and, while arresting one of the alleged vandals, were surrounded by about 500 youths.
July 2005, Papamoa
Baton-wielding riot police weathered a violent storm of bricks, bottles and abuse from more than 400 hyped-up youths at a party in Papamoa in Bay of Plenty.
About 24 officers swarmed the area with dogs just after midnight to herd the teenagers away.
Six arrests were made for disorderly behaviour - all males aged 15 to 19 - and two patrol cars had back windscreens smashed and panels dented. No one was injured.
What began as a 17th birthday party rapidly transformed the neighbourhood into a war zone when text messaging prompting an army of gate-crashers to converge on the area.
The violent teens - some of whom police say were intoxicated - refused to leave the area until police forcibly removed them.
