Emergency services are at the scene of a crash on State Highway 5 and Tutukau Rd.
Sergeant Phil Wilkinson said he understood that a camper-van and a rental car were involved.
A Rotorua Daily Post photographer, Ben Fraser, at the scene said there were two fire trucks and three ambulances present.
He said it looked like the crash happened on the bend just before the bridge.
Mr Fraser spoke with a tourist couple from Melbourne who were heading south and were involved in the crash.
He said they were not injured.
St John Lakes area territorial manager Hilary Morrish Allen said there were seven patients being treated for minor injuries.
Ella Berryman from NZ River Jet which is on the corner of State Highway 5 and Tutukau Rd said she heard a car screech on the road but didn't see what happened.
She said she could see a few cars and a campervan were involved in the crash.
"It's quite scary, I don't know how bad it is."
Owen Johnston, the driver of the camper-van, said it all happened so quickly.
"I didn't have a chance to do anything, it was all over in a few seconds," he said.
Mr Johnston said his wife Judy was a bit shaken up, but neither were injured. They were the only passengers in the camper-van.