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 tomorrow," 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 last night a member of the organising crew stood on stage and warned festival goers to check their tent as the river level was getting dangerously high.
Water started rushing through the main stage area at around 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."
He said water flooded straight through the truck and got as high as the tops of the truck's wheels.
Reaction on social media has been two-fold. People were commenting they were thankful everyone was safe but were questioning why the festival went ahead given the severe weather warning and recent flooding issues.
Organisers of Sundaise Festival have not been available for comment.
Hauraki District Council spokesperson Paula Trubshaw said around 40 of the 200 evacuees being cared for by Hauraki Civil Defence staff at the Waihi Salvation Army Hall have now been picked up.
The remainder of evacuees have gone home or to family and friends.
Nearby in Whiritoa, flooding on Mako Avenue has been worsened by sightseers driving past in cars, causing water to flush onto properties. People have been asked to avoid the area to prevent causing more water damage.
Just after midnight emergency services were called when festival goers became stuck and campsites were flooded, police said.
Around 800 people had been expected to stay in campsites near the festival however these people had to be accommodated when the area was flooded.
Many campers were taken in by local residents and housed in farm buildings and the Whatawhata Hall was opened up to provide shelter and people were taken to the Salvation Army in Waihi.
Buses were also organised by the Thames Coromandel District Council and Hauraki District Council to evacuate people.
Everyone was evacuated from the scene safely thanks to a good co-ordinated response from emergency services, council staff and festival staff.
Police and local authorities will be speaking with festival organisers this morning to discuss if it is safe for the festival to continue.