Police are appealing to the public for information to help find a man who they say was involved in an early-morning Christchurch assault.
Detective Senior Sergeant Nicola Reeves said a man punched another man in an unprovoked attack on Sunday, causing the victim to fall to the ground and hit his head on the pavement.
"The victim became unconscious and was transported to hospital where he remains," Reeves said.
The assault happened on Christchurch's Oxford Terrace at 1am.
"The offender was one of a group of Mongrel Mob who were socialising in town at the time and is described as Māori with tattoos on his arms, wearing black clothing, a black hat and a red bandanna wrapped around his wrist," Reeves said.
Many people were in the area at the time, Reeves said, and police believe some may have videos or photographs of the assault and/or the offender.
"Anyone who has information about the assault is encouraged to contact police on 105 quoting file number 210131/5776 or anonymously on 0800 Crimestoppers."