"Dooring" fines of up to $366 apply to all car users – not just the driver. Drivers and passengers face a $122 fine from police for creating a hazard, with courts able to impose a maximum fine of $366.

Last week VicRoads raised the issue of car passengers opening doors on cyclists on its Road User or Abuser Facebook page, part of a social media campaign to promote discussion about road use safety.

"We have limited road space and increasingly busy roads... we are mixing more road users in the same space and that means everyone has to be more considerate when using the road," VicRoads road safety executive director David Shelton said.

Bicycle Network Victoria spokesman Garry Brennan said the incidence of passenger doorings was far less than those caused by the driver, but because they were more unexpected they could be more deadly. He singled out passengers exiting taxis as a particular problem.

"No one does this deliberately, but they should be expecting bike riders in the street and act accordingly," Mr Brennan said.