Watch: Northland car surfer risks death in Parua Bay travelling up to 70km/h

An Auckland family of five were shocked to see a man standing on top of a car as it travelled towards Whangārei. Photo / Supplied

An eyewitness has expressed her horror upon seeing a man standing on top of a car travelling up to 70km/h towards Whangārei on Saturday.

Sarah McIsaac was travelling back to Auckland from the Whangārei Heads just after 2pm on Saturday with her husband and three young children. As they passed Parua Bay along Whangārei Heads Rd, they were shocked to see a man standing on the roof of a dark blue Toyota Hilux Surf, travelling between 50-70km/h. There appeared to be multiple people inside the car.

"We couldn't believe our eyes, who does that?," she said.

"I know young people do silly things at times but this was next level and the risk of something going seriously wrong was right up there."

As a mum, McIsaac's initial thought was to try and stop the car, but refrained from getting too close in case it caused the man to fall.

Instead, the whānau took photos and a video before reporting the incident to police. The car eventually pulled over so the man could retrieve a hat from the middle of the road.

"All I could think about was that young man's mum getting a knock on the door saying there had been an accident, which is a real possibility when you choose to stand on top of a vehicle travelling at speed," McIsaac said.

As a Mum, McIsaac's initial thought was to try and stop the car, but refrained from getting too close in case it caused the man to fall. Photo / Supplied

McIsaac said she was not only shocked by the man's actions, but by the participation of those in the car.

"Friends don't let friends travel on top of a moving car, it's that simple. If something happened to their friend they would have to live with that forever and face his parents knowing they did nothing to stop it.

"They also need to stop and think about those around them. They could've easily caused an accident or if he had fallen another vehicle could've hit him and they would have to live with that."

McIsaac said she used the incident as a lesson to her children - aged 4, 6 and 9 - about making wise choices and how real friendship meant speaking up when others made poor choices.

Northland District acting senior sergeant Ryan Gray said it was a silly thing to do and police were investigating the matter.

"This individual was egged on by his peers and could have been seriously injured or killed. The onus is on all of us to keep each other safe.

"If you have information about what happened please call 105."