Video has emerged of a violent fight between a group of girls at Ranui train station in Auckland.
Four young women can be seen punching and kicking another woman who does not retaliate, instead she falls to the ground as the beating continues.
Others can be heard egging the fight on saying things like "punch properly ow". One boy jumps in front of the camera grinning and pulling what's believed to be a gang signal.
Towards the end of the video, which was uploaded to the Paint Fade Facebook page, a boy in a red hat can be heard shouting "Stop! Stop!" before pulling the girls away from the victim.
Police say they are aware of the video and "are very concerned by the behaviour displayed in the video".
They are making enquiries about the incident and ask anyone with information to contact Henderson Police Station or call Crimestoppers anonymously on 0800 555 111.
It is not known when the fight took place.