Waikato resident's horror as man balances on car towbar going 50km/h

A Waikato resident spotted a man riding a car's towbar reportedly travelling at 50km/h this morning - and police want to know who the rider was.

A photo posted to the Residents of Rototuna/Rototuna North Facebook page shows a person in a white sweatshirt and shorts clutching to the back of a car with their feet on the towbar.

The member who shared the photo condemned the behaviour and described the incident as "not funny".

He dubbed the driver and rider "clowns" and asked members of the page who might know them to tell them to "pull their woolly heads in".

He said he reported what he saw to police.

Waikato District Command Centre Senior Sergeant Charles Burgess said the behaviour was "extremely concerning".

"It is not only illegal but very dangerous and could have fatal consequences. It is disappointing to see someone acting in such an irresponsible and dangerous manner."

Police are aware of the video and urge anyone with information to contact Hamilton Police on (07) 858 6200.

Information can also be provided anonymously via Crimestoppers 0800 555 111.

Video footage also emerged today of a motorcyclist's wild ride across almost the entire length of the Auckland Harbour Bridge on the rear wheel of their bike.

The clip, which was captured during a sunrise, attracted more than 1000 views since being shared Instagram this morning. It has since been removed.

The NZ Transport Agency has condemned the motorcyclist's behaviour.

The identity of the daredevil motorcyclist, clad in only a black T-shirt, light blue jeans and black sneakers, remains a mystery, but it appears the bike they're riding is a Harley Davidson.