A passing motorist has described the horrifying sight of injured children lying across the road and sounds of wailing moments after a car ploughed into a group of students at a school bus stop this morning.

North Shore resident Anna Grygorenko was caught in traffic on Wairau Rd when she drove into the rush-hour nightmare about 8.30am.

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Five people, including four students from nearby Westlake Boys' and Girls' High Schools - were injured when a car left the road and struck a group on the footpath.

At least one of the injured girls is fighting for her life in Auckland City Hospital.

An Auckland District Health Board spokeswoman said another was in a serious condition at the hospital and two younger children are in a stable condition in Starship Children's Hospital.

Grygorenko said as she wound down her window sounds of wailing soared over idling engines.

"There were lots of people and debris on the side of the road.

"I saw lots of kids in school uniform on the ground."

"I was driving past at the time and it must have just happened as no paramedics or police were on the scene yet.

"I lowered my window to listen for ambulance siren but instead I heard wailing from the victims," she said.

One girl was lying motionless across the road.

Vehicles were parked around the crash scene, apparently protecting the students from further harm.

"I think a couple of cars were parked the other way shielding the crash victims," said Grygorenko.

Many of those injured were lying across the road.

She said many people were gathered around comforting those who had been hurt.

"I'm still shaky," she said. "I can't focus at all. I feel badly because they are just children. I'm just hoping they all pull through."