A police officer kicked a man in the head while arresting him in Christchurch, an action that was "not justified", a watchdog has found.
The Independent Police Conduct Authority (IPCA) said the incident involved two officers who were called to a townhouse on Madras St in the CBD in March last year.
They were called to the property by neighbours because a man living there was drunk, hurling abuse and throwing things from his balcony.
He was initially given a warning but, a short time later, the officers returned to the house to arrest him for disorderly behaviour, the IPCA said.
"The man came out of his house and was handcuffed, with his hands behind his back. However, he became agitated and kicked the glass pane of the door with his bare foot," said an IPCA statement. "The man then lunged at one officer and was taken to the ground. The man also kicked the second officer in the head and upper leg while lying on his back."
According to the IPCA, the first officer warned the man not to kick his colleague - but he proceeded to boot his head.
"Immediately, the officer kicked the handcuffed man's head with his booted heel. The man's head hit the driveway and he was unresponsive for approximately 30 seconds," the watchdog said. "The officers called an ambulance, then took the man into custody."
The man later pled guilty to charges of assaulting police, resisting arrest and disorderly behaviour.
But the IPCA found through its investigation the kick by the officer was unjustified.
CCTV and social media footage of the incident indicated the officer could have stepped back and "re-evaluated" how to handle the man rather than kick him, authority chair Judge Colin Doherty said.
"The footage of this incident circulated on social media at the time and drew a negative public response. It is not hard to see why," Judge Doherty said.
"Further, the immediacy of the officer's response to being kicked in the head himself indicates a retaliatory action in my view."
What was also concerning about the incident was the officers failed to inform their sergeant the man had lost consciousness, the IPCA said.
"The authority looked at events leading up to the head kick by the officer and found that some of the language used towards the man was antagonistic.
"Having viewed CCTV footage of the incident, we did not accept the officer's assertion that he kicked the man's head to defend either himself or his colleague. Nor was the kick justified to overcome the man's resistance to being arrested."
In a statement, Canterbury Metro Commander Supt Lane Todd said the police's own thorough investigation was carried out into the incident.
"There are always learnings from incidents such as these and we always take the opportunity to look at what we could have done differently or better.
"While in general, we don't comment on employment matters, we will say the officer remains a member of the New Zealand Police."
