The driver whose packed school bus nearly toppled over an Auckland motorway overpass has been stood down.

Dozens of St Mary's College students were on-board the bus, which ploughed through the barrier on Newton Rd motorway overpass during rush hour on Friday.

The front end of the bus was left hanging off the bridge, with horrified passing motorists urging them to stay at the back of the vehicle to stop the bus from tipping over the edge.

Coachways New Zealand spokesperson David Marsden this morning said the driver had since been stood down, pending an investigation.

"As the matter is currently under investigation I can't comment any further.

"I am waiting on the report from police," he said.

The front end of the bus was hanging over the motorway bridge causing loss of balance. Photo / Matthew Lietz

Oncoming traffic was brought to a standstill as the bus was left straddling the busy motorway overbridge at Auckland's Spaghetti Junction.

Firefighters had to cut apart parts of the bridge fence and needed to hook the bus up to pull it out.

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An inflation device was placed under the vehicle to raise it up and then winch it to safety.

St John had said 24 people were assessed for injuries and one was taken to hospital with minor injuries.

Emergency services rushed to the scene of a school bus crash on an Auckland motorway overpass last Friday morning. Photo / Akula Sharma

A police spokesperson said there were no updates as yet and no charges had been laid at this stage.

St Mary's College principal Sarah Dwan praised first responders, who quickly arrived on the scene to help students trapped in the bus.

Dwan said it was fortunate that a staff member was in a car behind the coach and was able to offer immediate help.

"All our students are safe and well, and we are incredibly proud of how they have reacted and responded.

"Support is being provided for the students and their families and we will continue to support all involved.

"A staff member happened to be behind the bus on their way to school who was able to stop and provide support to our students."

Terrifying footage subsequently emerged of the incident.

The bus could be seen pulling onto the bridge before continuing to sweep in a circle, crashing through the barrier and coming to a rest dangling in mid-air.

The whole dramatic incident unfolded in just five seconds.

Firefighters had to cut parts of the rail barrier to winch the bus back on the road. Photo / Akula Sharma

The crash, which happened at 8am, caused extensive traffic delays through Khyber Pass Rd and Ponsonby.

The high school students on the bus were transferred to a nearby bus after being checked by St John ambulance staff.