About 200 festival-goers were rescued and the army called in to help clear up when torrential rain and a swollen river flooded the site of a festival near Waihi in the early hours of Saturday.
One performer, who was forced to move his tent and car away from the rising water, described the roaring river as "pretty damn scary".
The Sundaise Festival, held at Dickey Flat and due to run across the weekend, was cancelled and the army was called in to help clean up the sodden campground where cars and trucks had become trapped in mud.
Just after midnight on Saturday morning emergency services were called when the Waitawheta River began to rise.
Festival performer Marcel Currin said before the flooding everyone was having a great time. His set Poetry that doesn't suck went well and the rain forced people under cover to listen.
Mr Currin said things became confusing at his campsite on the opposite side of the river later that night.
"The level of flooding was unprecedented so I don't think anyone knew what was going on in our area and we kind of had to fend for ourselves and help each other out."
Mr Currin said everyone stayed calm but "the river was roaring and pretty damn scary, to be honest".
"It was a reminder nature can always be bigger than your plans."
Mount Maunganui mother Kristine Cook was evacuated with her 4-year-old daughter after watching her car get washed away by the river.
"Water was up to my knees. My car is gone. The motor does not work anymore so I had it towed out and will try to get it towed home," she said.
"My daughter got carried in her undies with a towel around her up to a hay barn, we ended up sleeping there."
As the deluge fell, a member of the organising crew stood on stage and warned festival-goers to check their tents because the river level was getting dangerously high.
Water started rushing through the main stage area about midnight.
The 28 house trucks of the Gypsy Extravaganza Fair and Market at the festival got hit hard by the flooding.
House trucker Tom James said one of his trucks was salvageable but another "got pretty hammered."
"It is buggered. Everything is pretty wet inside," James said.
He said water flooded straight through the truck and got as high as the top of the truck's wheels.
About 800 people had been expected to stay in the campsites near the festival.
Many campers were taken in by local residents on the night and housed in farm buildings and the Whatawhata Hall was opened up to provide shelter. People were also taken to the Salvation Army Hall in Waihi.
Organiser Matt Griffiths said before the event organisers made a decision based on the wet forecast to decommission two of the campsites closest to the river and move them to higher ground.
A little more than an hour before the evacuation began organisers made a warning over the PA system for people to go to their campsites and take their friends and families to higher ground at the information centre.
"We implemented our flood evacuation procedure for around 200 people and this went all according to plan," Mr Griffiths said.
There were no injures and all festival-goers were accounted for, he said.
Speaking to the Bay of Plenty Times from Dickeys Flat on Sunday morning Mr Griffiths said a crew was cleaning up the site but most of the work had been done the day before.
Thirteen army personnel were called in to co-ordinate the clearing of the site on Saturday, helping move stalls and vehicles trapped in the mud.
Hauraki District Civil Defence controller Steve Fabish said the site was "absolutely sodden" but by the end of Sunday, with army assistance, most of the struck cars were moved.
"Some vehicles had water in their engines and water inside and couldn't be started."
Mr Fabish would not comment on the organisers decision to go ahead with the festival despite heavy rain warnings and recent flooding saying: "I had a big enough job to do rather than analyse why or if".