A Fire and Emergency New Zealand spokesman said a fire crew removed the roof of a car to release a trapped and injured person.
A woman, who heard the crash before walking down to the scene, said one of the cars involved had split in two.
She said she heard high revs before the sound of a "really big thump".
"I'm sure that was the sound of the car hitting something and ripping apart."
A St John Ambulance spokeswoman said three people were transported to Whakatāne Hospital. One person was in a serious condition and two were in a moderate condition.
The woman said it appeared part of the car had become airborne with half ending up in a paddock and the rest on the road.
The driver was still in the half on the road.
"It looks like the drivers of the other cars had managed to escape serious injury but I'm sure the driver of the car that split in two was trapped."
She said emergency workers were searching through blackberry to make sure no one else had been in the vehicle.
Inside the police cordon on State Highway 30. Photo / Katee Shanks
The woman said there were a "heap" of people at the scene and it was very chaotic.
A person who worked in the area said the stretch of SH30 between SH2 and Western Drain Rd had been blocked off and police were directing traffic along other routes.
He said the crash happened on the bend outside the quarry, but the road was not usually dangerous because it was mostly straight with a slight bend.
