Police investigating motorbike wheelie along Auckland's Harbour Bridge

Police are investigating a video showing a man riding the entire length of Auckland's Harbour Bridge on his motorcycle's rear wheel.

Posted to Instagram, the footage shows a Harley Davidson driving along the left-hand lane of the bridge, and is filmed by someone in the lane to the right. User jos_bike_lifestyle says it is a "world first".

Within four hours it already had more than 1000 views, but Sergeant Richard Byrne from the Waitemata police says the act could have had "fatal consequences".

"The behaviour of this motorcyclist shows a complete lack of regard for their own safety and the safety of others.

"Police are very concerned about this sort of behaviour and will be making enquiries into this incident."

Auckland Transport operations manager Rua Paul tells NZME it is "reckless and dangerous".

"It poses a huge safety risk for the motorcyclist and all other road users.

"We'll support the police in any way to identify the person or persons involved."

Anyone with information on the incident is asked to contact police on (09) 477 5000. Information can also be provided anonymously via Crimestoppers on 0800 555 111.