Camp staff and police have been blamed for inflaming the massive New Year's Eve riot in Gisborne which ended in 63 arrests and 83 people being injured.
The large-scale disorder broke out across two campgrounds being used for the BW Summer Festival.
Police battled with the drunken mobs for three hours.
Officers were pelted with cans and other objects, vehicles were overturned, fights broke out, and several fires were lit.
"It was pure luck that someone didn't lose their life," said Tairawhiti area commander Inspector Sam Aberahama.
Videos have started to emerge that show the extent of the carnage.
Beer cans and other missiles are seen being thrown between groups across two campsites.
Festival goers can be seen sheltering under air mattresses to protect themselves.
One eyewitness took to online social forum Reddit to hit out at camp staff and police for their role in the escalating drama.
The poster, Heavy--Metal--Viking said small fires started getting lit at around 4pm and were dealt with by staff.
Around the same time, campsite portaloos were locked and barred by staff.
"This just frustrated campers, and plenty of guys just dropped trousers wherever they felt like it," the poster said.
At 6pm, a mob rushed the "prison style" fences and pushed it over.
Groups then started hurling full cans at each other.
"Another contributing factor is that campers where unofficially advised to pack everything away and take down gazebos and tents, because of people jumping into them to break them," the poster said.
"So the entire site is visible from any point because of the lack of obstructions. Any small crowd attracts bored angry teens."
Police started to "funnel" the campers toward the entrance at around 7pm, the poster claimed.
But the move created a "chokepoint" and a "big mob".
The poster said only one Rhino vehicle was tipped on its side, and not any other vehicles.
Fires consisting of air mattresses and tents were then made.
"Police where totally overwhelmed by the volume and scale," said the eyewitness.
Police said the riot was well-planned and coordinated by a core group of festival-goers who were "intent on causing trouble".
There was an "extremely high" level of intoxication, said Mr Aberahama.
He said there had been trouble at previous festivals, but last night's riot had been the worst.
"This was an intentional riot that was fuelled by alcohol. It was obvious a plan had been put in place by the main agitators, which quickly spread through the campgrounds. We used every available police resource to try to keep control of the crowds," Mr Aberahama said.
Mr Aberahama said police were extremely concerned about the level of disorder.
"A definite mob mentality quickly developed amongst the crowd. It was dangerous for everyone - festival-goers, police, ambulance staff and security staff."
BW Summer Festival is touted as New Zealand's "premier beachside camping festival". It runs alongside Gisborne's Rhythm and Vines, and hosts up to 15,000 campers for five days, featuring two nights of concerts at the Soundshell outdoor theatre.
About 7000 people attended the festival, in which campers could bring unlimited amounts of alcohol into the campsites.
The BW festival was granted a special licence, but a decision was made by festival organisers to revert to a BYO status after pressure from festival-goers who had already purchased tickets.
Police did not oppose any licence applications, but supported the special licence application.
The nature and seriousness of the injuries was not specified early today.
St John Regional Manager Stephen Smith said most of the injuries were from projectiles being thrown. People were also injured during crowd surges.
"There were a number of people who weren't interested in causing trouble and just wanted to have a good time without incident. It's a shame they had their night ruined."
Police said those arrested would face various charges ranging from disorderly behaviour to assault.
Mr Aberahama said police resources and festival security staff were stretched to the limit and extra staff had to be called in from the Rhythm and Vines festival.
Earlier today a photograph was posted on the Hawke's Bay and Gisborne Police Facebook pages of "the oven" - a facility to house troublemakers onsite.
"This is where you may end up spending your New Year's Eve at BW Summer Festival if you don't play by the rules," the post said.
"It has the most up-to-date shiny chrome trendy interior decor and is compact enough to hold 20 guests at a time. It also comes with high-level security grills so you don't feel unsafe.
"There's not much air-conditioning so you will be all snugly and warm. It's all onsite so you don't even have to leave your camping ground. And did we mention there are four of these lovely little chalets, all waiting for guests. We're taking bookings now for tonight, so get in quick before the rush. "
