Footage from a shocking crash on Auckland's Southern motorway shows a passenger appearing to attack the driver after a car slammed into a concrete barrier.

Police say one person was taken to hospital after the crash but that no-one was seriously injured.

A video of the incident was captured by another motorist and shows the car swerving across three lanes at speed to then crash into the barrier.

Debris can be seen flying off the car and it then swerves away to the right side of the motorway.

A motorist who witnessed the incident just before 7.45pm on Wednesday told the Herald the "very fast" car came out of nowhere.

"I was suspecting they were fighting and that's why it happened. Although the car was fast all of a sudden they went full steering turn."

Moments later, two people ran out of the damaged car.

The pair then appear to enter into an altercation with each other near the front of the car. Not long after the driver falls to the ground.

The witness said he then saw the passenger appear "hit" the driver.

"The person came out of the car and then the driver came out and he [the passenger] started hitting the driver and then the person [the driver] fell down."

"I was so lucky even if my car was a little faster or something they could of hit my car," he said.

A police spokesperson said officers were looking into the crash.

"A crash was reported in northbound lanes of the Southern Motorway near Takanini at 7.46pm on Wednesday night," the spokesperson said.

"No serious injuries were reported, but at least one person was taken to hospital," they said.