Police officers were unlawful in pepper spraying and arresting a man outside a petrol station in Porirua last year, the Independent Police Conduct Authority (IPCA) has found.
Footage of the incident emerged last year on Facebook, with videos showing a man being pepper sprayed by police, tackled to the ground, and having a dog set on him.
In a report released today, IPCA chairman Judge Colin Doherty said the incident was not only unnecessary but unlawful.
"The actions of a Police officer in attempting to prevent a man going about his lawful business promoted a violent confrontation.
"The Police officer acted contrary to law and did not demonstrate good judgment during this incident."
The authority did not accept that the officer believed the man posed an imminent physical threat to him.
"Therefore the use of pepper spray was unjustified. However, the authority found that the subsequent use of force was lawful, due to the man's violent reaction when responding officers attempted to secure him," the report said.
Police acknowledged the findings of the IPCA report which determined that the pepper spraying of a man, and the man's subsequent arrest, were unlawful.
Police investigated the incident and an employment investigation was undertaken into the officer's actions.
The outcome of that investigation was an employment matter and police were unable to comment for privacy reasons.
"We set high standards for ourselves in NZ Police and strive to deliver policing to those high standards," Acting Wellington District Commander Inspector Chris Bensemann said.
"Unfortunately there were mistakes made during this incident, which we can learn from."
All charges laid against the man involved in the incident were withdrawn in November 2017.
The incident happened at a Mobil Porirua petrol station in April.
"We're not disputing the obstruction charge or the resisting arrest charge, we want the amount of force used investigated and [charges of] assaulting an officer twice dropped [sic]", a friend of arrested man who posted the video on Facebook said earlier.
"He never assaulted anyone."
At the time, the footage had nearly 400,000 views, as well as thousands of likes and shares.
The routine stop in the early hours of the morning on Kenepuru Drive quickly escalated out of control when the poster claimed police used pepper spray on her friend as he tried to buy cigarettes.
She detailed in a post how the man went to buy cigarettes, but didn't return to his car when asked by police. While not shown in the footage, it was alleged the man was pepper sprayed after he walked away from the police officer.
The situation escalated when one woman confronted the police officer, asking why the man was pepper sprayed before he fled from the officer to his partner on the other side of the station.
The footage shows a dog being retrieved from a police car before the man slips and is tackled to the ground by one officer. Another comes into view to hold the man down while trying to handcuff him.
The footage is split, but returns to show a dog pulling at the pants of the red-faced man being arrested.
Kapiti-Mana area commander Inspector Tracey Thompson said at the time the man had been charged with resisting arrest, obstructing police and two counts of assaulting officers.
The post said the man suffered a black eye, cuts, numerous bruises and bruised nerves to one of his thumbs.