A Christchurch police officer videoed calling a woman a "skank" and shoving a man to the ground after a student party is now the subject of an official complaint.
Police confirmed they were investigating the incident after officers earlier arrived on Waimairi Rd in Ilam about 11pm yesterday to quell a party of about 200 revellers.
A man - who lived up the street and filmed the later altercation - said the "student" party had been going a few hours before it spilled on to the street.
Police began arriving and building up their numbers before forming into a line to sweep the partygoers out of the area.
That led to a number of arrests, the man, who did not want to be named, said.
However, the officer filmed in the video can be seen trailing behind his colleagues, who earlier moved up the street to arrest another person.
It was then a group of four people called out to the officer: "Hey, he's done nothing wrong".
The officer responds that he had warned the group to go home.
"Leave the area now or you will be arrested," he said.
The group say they haven't done anything wrong before one of the women says she will "tell my police officer father".
The officer asks "who's that", before starting to walk away while saying: "I'm sure he's really proud of having a skanky daughter in the streets swearing at the top of her head".
That prompted a man from within the group to say: "Don't f*** call my missus skanky".
The man can be seen standing still on the footpath.
But the police officer turns and walks fast towards him before shoving him hard in chest, flinging the man off his feet and on to the footpath.
The officer appears to point down and swear at the man.
"You were told to go home, now go home."
Climbing to his feet, the man responds "you're the man bro" to the officer.
The officer then walks away, saying "boohoo" to complaints from the group.
Canterbury District Commander Superintendent John Price said police were aware of the video.
Police had received a formal complaint into the officer's actions and an investigation had commenced into what led to the incident and its filming, he said.
"NZ Police have high expectations of all our staff that they will exemplify police core values in every interaction with the public.
"We have zero tolerance for unjustified violence in our communities. Any behaviour that does not meet the standards expected of a police officer in this regard is unacceptable and will be investigated."
The man who filmed the video told the Herald that in his view the officer did everything wrong "in that situation".
"He shoved that guy on to the ground, and then walked off and he was like 'boohoo' and doing this childish sort of stuff."
"It showed a complete loss of control in that situation."
The man said he hadn't been to the party and didn't know the group involved in the altercation.
He was filming because the incident took place outside his front gate, he said.
The other officers had handled themselves well in dealing with earlier difficult partiers.
Just moments before the altercation on video, another aggressive person at the party had been swearing and throwing things at police and was subsequently tackled and arrested further up the road, the man said.
By the time of the incident, however, police had mostly restored calm, he said.
"The whole situation was relatively under control and that level of force from him wasn't needed in that situation."