Footage of a "vicious and cowardly" attack showing a young man in Auckland being knocked unconscious by an attacker using a piece of wood has been released by police.
The attack was part of a violent fight between two groups of two men on Oates Road in Glen Eden about 11pm on January 23, police say.
A 20-year-old man suffered serious head injuries in the fight, Detective Sergeant Chris Goldsmith says.
"This is a particularly vicious and cowardly attack on a male who continues to be struck in the head with a plank of wood, despite lying unconscious on the ground," he said.
"We had to leave out the last part of the footage as it was too graphic to show. However, the offender strikes the victim in the face while on the ground in what easily could have resulted in a fatal blow."
The man's two attackers ran towards Captain Scott Road straight after the fight, police said.
They are yet to identify the pair, despite pursuing "several lines of enquiry".
In a bid to track them down, the family of the man pictured being hit have given their support to police to release footage of the attack, Det Sgt Goldsmith said.
The first "main offender" in the footage is described as of Polynesian ethnicity with a large afro hairstyle, solid build and about 1.82 metres - or six feet - tall, he said.
The second man is described as being Maori or Polynesian, about 1.75m tall, of a fit build and dressed in a white t-shirt.