A police officer's use of an unapproved "hold" to knock a man consciousness was an excessive use of force, the police watchdog has found.
The "carotid hold" involves cutting off the blood flow to a person's brain by squeezing the neck until they lose consciousness.
On May 10, 2016 an officer responding to a domestic violence incident used the tactic on a 36-year-old offender after pepper spray was used to no effect.
The officer then proceeded to punch the man and use the carotid hold despite it being removed as an approved tactical option.
The man complained in October of that year that the the officer had "choked him out" until he lost consciousness and that he was also punched multiple times.
In a decision release on Thursday, the Independent Police Conduct Authority found the officer's decision to use pepper spray and to punch the man was justified but the use of the carotid hold was not.
"Given the risks associated with the carotid hold, which the officer knew or ought to have known about, the authority does not consider that the officer was justified in using it since the man's behaviour did not pose a threat of grievous bodily harm or death," Authority Chair Judge Colin Doherty said.
The authority said while the hold was no longer an "approved tactical option", it was not banned.
Replying to the criticism, police said the man was a Mongrel Mob member of solid build with previous convictions for violence.
"Our staff regularly have to deal with aggressive members of the public and are forced to make split-second decisions under pressure to protect both themselves and the community," Superintendent Sam Hoyle said.
"In this situation the officer was by himself and faced a physical confrontation with a man who was wanted for arrest for violent offences and was physically resisting arrest."
The IPCA said the man had received appropriate medical care after the arrest.