A witness has described the moment a black Holden Commodore pulled over and then carried out a U-turn - with a bus driving right behind it.

Tokoroa local Pam Bull watched as the bus slammed into the side of the Holden, pushing it through a fence and into a paddock 20m away.

The crash happened around 4.20pm on State Highway 1 near the intersection of State Highway 30, south of Tokoroa.

Four people were injured and the car's driver had to be cut free after the right side of the Holden was smashed up by the bus.

Advertisement

The GoBus had just one passenger who has some cuts on his leg, Bull said.

"He's been talking to us but he sort of doesn't know where he is," Bull said. The man was middle-aged and known in Tokoroa.

The bus driver, an "older gentleman", has lacerations and reported it hurt to breathe, she said. Wire from a paddock fence had wrapped around the bus and trapped him inside; emergency service personnel were using wire cutters to get him out.

The two younger men in the Holden had been cut free by rescuers. One was getting in an ambulance, Bull said. "He seemed quite responsive but the other one was going in and out of consciousness."

Both vehicles were travelling toward Tokoroa, Bull said. She was shocked when the Holden attempted a U-turn, saying it was "blindly obvious" there was a bus coming.

Northern fire communications shift manager Scott Osmond said four people were hurt in the crash.

The fire service was called at 4.22pm. Two fire crews have arrived from Tokoroa and a third from Rotorua, Osmond said.

The driver of the car was trapped and was being freed by fire crews with rescue equipment.

Advertisement

Police and ambulance officers are also at the scene.