Horror ride: The scary 15 seconds packed school bus careened out of control on East Auckland street

A teenager on a packed school bus has described the terrifying 15 seconds when the vehicle careened across an east Auckland road bowling everything in its path.

Howick College pupil Campbell Allan says the ordeal left pupils with whiplash and at least one with a black eye, but reckons had the roads been busier the crash could have been deadly.

The bus, packed with up to 40 Year 9 and 10 pupils, was heading along Chapel Rd when the driver suffered a medical event.

The out-of-control bus veered onto the right-hand side of the road, ploughing into parked cars and sandwiching them together as it came to a crashing halt.

"It could have been way worse. There were no oncoming cars on that side of the road and if that had happened that would have been terrible," said the shaken teen who headed back to school today.

"It all happened so fast. People were shoved forward in their seats.

"At first there was a big bang like metal against metal as it hit a car and then there was loud rustling and noise from the trees and ground that was pulled apart and there was dirt on the windscreen and side of the bus.

"It seemed like it was happening forever because the bus was going so fast that it didn't seem like it was going to stop.

"We were like, 'thank God' when it did."

He said the Murphy's Line school bus was 15 minutes into a routine trip home when things took a dire turn.

The Year 10 pupil, who was sitting near the back of the bus, said pupils noticed something was wrong when the driver failed to cross an intersection and vehicles waiting behind started tooting.

"For about 10 seconds he didn't move when the light was green, which was interesting but then he drove off after a couple of beeps."

Allan, 14, said he later learned several pupils noticed the driver starting to slump to one side seconds before the impact.

"Then suddenly he didn't steer and he drove off the road," recounted the pupil.

"At first he appeared to be driving at the speed limit and then it felt like the bus was going faster than usual right before the crash.

"We noticed he was steering on to the right side of the road and a lot of the kids started shouting 'Yo, what's going on?' and swearing and everything until we hit. Lots of girls were squealing.

"The actual impact lasted for about five seconds because we were going through debris before we hit the cars. We hit trees, poles, everything."

Allan said there wasn't time to take evasive action for those seated on the right-hand side, which bore the brunt of the impact.

After crashing into a line of cars parked outside nearby shops, Allan said pupils, desperate to get out, then couldn't open the main escape route.

"The doors wouldn't budge because the driver had a button. We were thinking what if we have to smash the glass but eventually we had to forcefully push open the door and we all rushed out."

He said he was "extremely" relieved to get out of the wreckage.

"I didn't know where we were or what had happened so once we got out that's when it actually hit us."

Allan, who is back at school and planned to bus home as usual today, said most of the pupils escaped without serious injury.

"The majority of the kids were untouched - they just got shoved forward - but a [boy's] eyebrow had blood on it and he has a black eye now."

St John said a seriously injured person had been taken to Middlemore Hospital and three other people had been treated at the scene.

Two of the three had minor injuries, and the third was moderately injured, said a spokesperson.

Today Howick College principal Iva Ropati said some students were quite "shaken up" by the crash but were doing well.

Counsellors were contacting them but none reported needing any further support, he said.

The school had also contacted the bus company yesterday, and confirmed the driver sufferred a medical event at the wheel.

Ropati said the school was extremely pleased with the way the students coped throughout the ordeal.

A spokesperson for Murphy Buses today refused to comment on the crash.