A police officer who struck a man at least four times while trying to remove him from a patrol car in Waihi in western Bay of Plenty used "excessive force", the Independent Police Conduct Authority has found.
Police said they stopped the man about 4.30pm on December 28, 2019, after receiving two reports of him driving dangerously.
The man was taken into custody after failing a roadside breath test and then became argumentative with police.
He was required to accompany an officer to the patrol car for an evidential breath test, but police said he became "aggressive and resistant" and two other officers were called to assist.
Due to his behaviour, they decided to take the man to Waihi Police Station for the test but once in the patrol car the man refused to get out again so officers could search him before travelling.
"While trying to remove the man from the car, one of the officers used unnecessary and disproportionate force, striking him at least four times," the Authority said.
"At the time the officer struck the man, both of his wrists were being held by officers, he was leaning away from them, and no weapon had been seen. He was not posing an immediate risk to the officers," Authority chairman Judge Colin Doherty added.
In response to the findings, Waikato District Commander Superintendent Bruce Bird said the officers were "confronted with an aggressive and highly intoxicated person", adding they "had the very best intentions when dealing with the matter".
"Our staff come to work every day to keep our community safe and, in any situation, the use of force is an absolute last resort."
The Authority also found that the officer did not complete a report about his use of force.
Bird said police accept that a tactical options report should have been submitted, as is required by any staff member who uses force.
"This has been addressed with the officer via an employment process."
Following the incident, the man received ongoing treatment for shoulder pain which was attributed to another of the officers attempting to pull him from the car.
The Authority found the technique used by that officer was "poorly executed".
This same officer also placed his knee on the man's upper shoulder and neck area while he was restraining him on the ground, but the Authority accepted the use of force was unintentional.
"However, the officer then deliberately placed his knee on the side of the man's head in an attempt to control him. This is not a restraint technique that should be used," the Authority added.
The officer has since completed further training in this area, Bird said.
The man was charged with driving with a breath alcohol level of over 400 micrograms per litre of breath and resisting arrest.
He pleaded guilty to both charges.