An attack on a cyclist at a popular Christchurch trail has beem caught on camera and posted online.
YouTube user jb12321, whose first name is Jordon, uploaded the video on YouTube with a message to contact him if anyone recognised his attacker.
He also posted it on social news website Reddit, where he explained the incident at the Flying Nun trail on Christchurch's Port Hills.
"I started out by me asking him to let me past on the track. He kept saying 'yes' but wouldn't give me a space. He was holding me up pretty badly. Trail etiquette says you pull over to let faster riders by," Jordon said.
Jordon said when being polite stopped working, he told the slower cyclist he was "rude" for not letting him pass.
"You can see how it unfolded in the video. He tried to strangle me with my helmet while he was trying to steal my camera, and when I started yelling for help he put his hand over my nose and mouth. It was like he'd done it before.
"I was getting pretty fearful for my life by that stage so I did the only thing I could do without letting go of the camera, bit down on his finger. That got his hand away."
Jordon said when he eventually managed to make it to a nearby road to call police, the man turned up again and tried to get him to delete the video.
"He then tried to get the other two guys I was with to turn on me, by saying I assaulted him and showing them his finger. I was just like, if you didn't assault me, what was your finger doing in my mouth."
The video has had more than 2500 views.
Warning - video contains strong language and