A man who says he witnessed an assault by two protesters on another occupier at Parliament says it shows how the mood has turned nasty at times this week.
Violent incidents at the occupation, which started more than two weeks ago, have increased this week.
Yesterday, a car tried to plough into a group of police, and faeces and another unknown substance were flung at officers.
A number of officers and protesters have been injured in clashes since police installed concrete bollards at the protest perimeter on Monday, and there were injuries on both sides earlier in the protest during an attempted police crackdown.
On Monday, a protest "intermediary", former New Conservative leader Leighton Baker, received death threats from fellow protesters after failing to pass on a message about a police operation.
Horrifying assault shows mood turning at protest - eyewitness
Michael - who does not want to be fully identified over safety fears - lives in the CBD and works right next to the cordon.
He said the scary vibe around the grounds at the start of the protest mellowed last week.
But his perception changed on Monday when he was walking past the packed food facilities on Molesworth Street about lunchtime.
He said out of nowhere, he saw two men king-hit and then kick a protester.
"One guy pushed this guy forward and the other guy kicked him in the head - his head was about four feet off the ground when he kicked him, so it was like watching someone kicking a football.
"He fell to the ground and these guys started kicking him.
"If you had said to me two weeks ago I would see someone get their head kicked in and stomped right in front of Parliament, I would say 'absolutely no way'.
"So it goes to show how far we've come."
Michael said it was the most horrifying example of street violence he had ever seen, and was terrifying.
He wolf-whistled to draw attention to the alleged attack and the man - who had a large cut on his head. The man was picked up by protesters and carried into Parliament's grounds.
Michael ran to officers around the corner, but by the time he and police got back there was no sign of any of those involved.
Michael said there was no way he would walk through the protest area now, as it seemed lawless there.
"It goes to show how quickly things can get violent, and this is extreme violence."
RNZ has approached police for more information about the attack.
Yesterday, Police Assistant Commissioner Richard Chambers said there had been disturbing behaviour from people at the protest intent on aggravating the situation.
But he reiterated that police were making progress with protest leaders and were happy with the people they were talking to.
While there have been incidents of violence, large numbers of protesters have also been calling for others to calm down and have tried to keep the situation from escalating.
Protesters have established internal security, and appear to be working to try and quell those who are lashing out in confrontations.
Meanwhile, Wellington Girls' College, which is about half a kilometre away from Parliament, said students would learn from home for the rest of the week, because the protest meant it was not safe for them to come to school.
Protesters say they are shocked by behaviour of some, demand police help
A group representing protesters at Parliament say they are shocked by the "alleged violent and antisocial behaviour" displayed by some at the site in the past two days.
It said individuals responsible for flinging faeces and another substance at police were wearing masks and were not known to protesters.
The group said it wanted police to do more to work with organisers to remove known perpetrators, and accused police of inaction as a way to make protesters look bad.
The group said it had sought to work with police to identify individuals involved in any criminal acts and maintain a "safe and peaceful environment".
A number of officers have been injured in clashes in recent days and the group said it had passed its sympathies to them.
In a separate statement, one of the groups at Parliament linked to the Destiny Church said "extreme fringe elements" at Parliament were trying to "hijack genuine efforts from protesters".
The Freedom and Rights Coalition said it wanted to bring confidence back to peaceful protesters at the site.