Man filmed slapping Perth cyclist from passing car

People are demanding a car passenger who was filmed hitting the bottom of a Perth cyclist as he drove past be slapped with a fine for his dangerous actions.

The video shot by a camera attached to the unidentified bike rider was posted online on Sunday night by the website cycle.org, which has called the man’s actions "stupid and dangerous".

The camera pointing behind the cyclist shows a sliver Ford slow down as it approaches the rider on Anchorage Drive in Mindarie.

The man with a cigarette in his mouth then winds down his window and leans out to slap the backside of the cyclist.

"This is stupid, dangerous and has caused major crashes. This passenger should be re-educated," cycle.org wrote.

"We have no details yet. But we feel this is as close to a hit and run without injury, it is still a hit and run."

Other social media users also condemned the “f---ing weak p----” who they said should be reported to police and fined.

Anyone with information can contact Crime Stoppers on 1800 333 000.