A veteran policeman criticised by the police watchdog for "stomping" on an arrested man's head has already been dealt with but will keep his job.
The officer, who stood on the man's head during an arrest used excessive force and the act was unlawful, the Independent Police Conduct Authority has found.
Three officers had restrained the man suspected of burglary in Mangere East last year when the fourth officer brought his foot forcefully down on his head at least twice, the authority said.
The man, who had been resisting arrest in late December, was lying on the ground, face down, when the officer - who had been a policeman for 20 years - arrived on the scene.
The other officers later complained, saying he had stomped on the man's head, describing him as "quite aggressive".
The arrested man was described as screaming and bleeding from his ear.
A police spokeswoman said the officer was still a member of the police force.
"An employment investigation was conducted and the outcome of that investigation remains confidential to the parties concerned," she said.
She declined to say what action had been taken or if he had been rebuked.
The officer claimed he thought the man may have been armed and was only trying to keep him from hurting himself, but the authority said his justification for his action was untenable.
The authority accepted the man being arrested was struggling and a medical report found he had no head injuries, but said the force used was still excessive.
"There were other less violent ways in which that could have been achieved. His actions therefore constituted excessive force, were not justified in the circumstances and were contrary to law," authority chairman Sir David Carruthers said.
No weapons were found at the scene.
The IPCA does not have enforcement power and although it can make recommendations to police, it has not made one in this case.
Superintendent Richard Chambers said although the police accepted the findings, the threshold for a prosecution was higher than the authority's.
"While it's disappointing that one of my staff has been judged by the authority to have used excessive force during an attempted arrest, I accept that, in all probability, he could have used a less forceful option," he said.