An "escalation in concerning behaviour" among protesters was behind the police's move on those occupying the area outside Parliament today, New Zealand's top cop says. 

The harm being done far outweighed any legitimate protest, Police Commissioner Andrew Coster said. 

The operation began just before 6am on day 23 of the occupation when police moved to all of the key sites around the perimeter of the protest area, pulling down tents and clearing protesters and their vehicles. 

Coster referred to the occupation as "one of the most significant events in our recent history". 

Thirty-six people have been arrested for a range of offences from willful trespass to obstruction, he said. 

Fifteen vehicles have been towed so far, and will not be returned in the immediate future, he said. The operation had been planned for a number of days and a lot of officers have been deployed to Wellington from around the country, Coster said. 

"Our intent is to clear public roads and restore order," Coster said shortly before midday. 

Police's message to those who do not want to be caught up in the operation is "please go home", Coster said. 

"We're seeing people get the hint, and take their belongings and leave," he said. 

"There is no interest here in anyone turning this into a fight," he said. 

Why police moved after 23 days 

"We reached a stage where protest leaders were either unwilling or unable to effect change," he said. 

"There has been a change in the make-up of the crowd lately." 

"They have observed an escalation in concerning behaviour, hence today's operation," Coster said. 

Nothing about this protest had been acceptable, he said. 

"We have hundreds of additional officers from around the country. We have from the start endeavored to de-escalate this situation, it has not been our desire to put our staff and others at risk. It has now tipped over a balance and has to end," Coster told reporters. 

Police will continue to arrest and charge people where necessary and continue to seize vehicles throughout the day. 

On the presence of children, he would ask they are removed from the site altogether. 

Coster said he was "very happy" with how things had gone today and believed officers, had been "extremely patient and extremely restrained". 

"We saw weapons, we saw shields, we saw barricades - I am very happy with the police response." 

"The tactics that police bring need to balance acting and not acting ... and I believe we've got it about right." 

He said pepper spray had been used in response to protesters directing a fire extinguisher at police officers. 

Asked about the occupation being a Covid breeding ground, he said there was a Covid outbreak all over the country. 

Asked about the claims of protesters throwing human waste last week - which is denied by many protesters - he said that claim was true to his knowledge. 

He said the pointing of a laser at the helicopter this morning was a serious offence, and they would be looking to identify and prosecute whoever was responsible. 

The operation so far today 

Officers have now reclaimed the ground in front of the Parliamentary library and around St Paul's Cathedral opposite. As yet, police have not moved into the main protest area on Parliament's lawn itself - the barricades and tents are all remaining and protesters still stand at the barricades there. 

The action has resulted in some violent confrontations. In Molesworth St police armed with riot shields moved down with officers dismantling tents and shoving protesters out of the way. Some protesters could be seen throwing objects, screaming abuse, and confronting officers. 

Protesters hit by pepper spray were using water from the two pools outside the Court of Appeal building to flush their eyes. 

Police have largely cleared vehicles and protester camps on Aitken and Hill streets, although some remain on Molesworth. The area around Victoria University's Pipitea campus also seems to still have protest campers on it. 

Police have arrested about 60 people and some police and protesters have been injured. 
In statements, they said it was pleasing to see some protesters leaving voluntarily, and they were on hand to help others who wanted to leave. They also asked people to take children away. 

The Freedom and Rights Coalition - one of the groups involved in the protest - has put out a statement decrying police action, saying the majority of the protesters there are peaceful. 

"These people have lost so much due to the mandates and are only in Wellington as a last resort. All other avenues for discussion and debate have been shut down on them.