An angry automotive exchange on the streets of Christchurch.

A Christchurch builder caught on camera in an alleged road rage incident admits he should not have been using a cellphone while driving, but says people should not take the law into their own hands.

A male motorcyclist recorded the incident on a camera strapped to his helmet on Wednesday afternoon.

He had seen builder Warrick Anderson using a cellphone while driving on Colombo St and gestured to him that he should switch the device off.

The motorcyclist, who did not want to be named, claimed Anderson tried to cut in front of him several times as they drove north on Colombo St and turned left onto Moorhouse Ave.

When the pair stopped at a set of traffic lights, Anderson got out of the van and began verbally abusing him, he said.

"This was the most aggressive run-in I've ever had."

Anderson said he was "utterly apologetic" for using a cellphone while driving and should not have stepped out of the van to confront the motorcyclist.

He was frustrated that footage of the incident posted online had been heavily edited though and did not show the motorcyclist overtaking traffic or "pulling the finger" at him.

"I was actually trying to be quite calm, but who would last 10 kilometres of him going up and down the road."

The motorcyclist had posted videos of other run-ins with drivers online, which made it seem like he was "just playing the vigilante", Anderson said.

"He's not doing good at all. He's upsetting people, he's making people angry on the road.

"There's processes – ring *555 if you're going to complain."

Anderson said he had received several abusive emails and text messages since the footage was uploaded, including death threats, which he planned to speak to police about.

He was "seriously gutted" by the video and worried about how it would affect his business.

"I'm not a bad guy. Vigilantes like him, they have a problem – don't take the law into your own hands."

The video of the incident has been viewed more than 86,000 times on the LiveLeak website since it was uploaded on Wednesday.

The motorcyclist said he gave police the unedited footage of the incident on Thursday.

A Canterbury police spokeswoman confirmed the incident was being investigated, but it was too early to say whether any action would be taken.