WATCH: Man dragged along road in bizarre road rage incident

Shocked witnesses tried to step in as a man was dragged along a Perth street in a bizarre road rage incident.

When they realised they couldn't help, they decided to capture the dangerous incident on camera.

A man can be seen with his arm through the window of a Suzuki Swift.

A man thrusts his arm through the window of a car in Scarborough. Source: 7 News

Suddenly the driver accelerates and the man is dragged along the road for several metres.

Suddenly the car takes off and the man is dragged along the road. Source: 7 News

Witness Alexis Alveyera saw the incident unfold on a Scarborough road at midday on Thursday as he was moving house.

"We were like, 'what's wrong with them? They're going to get hurt, or hurt someone'", he said.

Alexis Alveyera was a shocked onlooker. Source: 7 News

"We went first to see if the driver was alright because we thought the guy was punching her or something, but no, it was not the case.

"I think he was just trying to get the keys."

It's not clear how the incident started, or why, but Mr Alveyera said the man looked seriously hurt.

The man pictured here was later dragged along the road for several metres. Source: 7 News

"He was already hurt because he put the window up, his arm was stuck in there," he said.

"And his leg was dragging on the ground. Yeah, his legs were really rough."

The police were called, but by the time they arrived both the driver and the victim were gone.