At least 120 protesters have been arrested on Parliament grounds, police have confirmed.
Two police officers have been hurt and some of those arrested had minor abrasions.
The anti-mandate demonstration is in its third day.
There had been 150 extra police brought in, on top of the 900 staff already in the city, Wellington District Commander Superintendent Corrie Parnell said.
Police and parking wardens were issuing infringement notices to vehicles parked along streets in front of Parliament and on the footpath near Lambton Quay.
Parnell anticipated removing the protesters could still take a matter of days.
"This is unprecedented for New Zealand. We've never had an occupation of this scale and certainly with tents on Parliament grounds, so some degree uncharted waters.
"It was never going to be a short process."
He said police had taken a "measured, graduated response" and police had worked hard in engaging with protest organisers.
At least 120 people had been arrested throughout the day.
"This was never going to be a short task.
"We do acknowledge the fundamental lawful right to peaceful protest. However, we have clearly seen a transition to activity that is impacting common New Zealand public."