Police say leaders of the anti-mandate protests at Parliament grounds have lost control of unruly members within the crowd.
In a statement, a police spokesperson confirmed a 35-year-old man was arrested inside Parliament grounds last night and charged with inciting violence.
The man is due to appear in the Wellington District Court next week.
It was estimated there were about 300 vehicles inside the cordoned area this morning.
However, Police say they are concerned by the deteriorating conditions at Parliament grounds and urged people to stay away from the protest due to 'extremly poor' sanitary conditions, aggressive behaviour within the protest group as well as the presence of Covid-19.
"Increasingly, key protest group leaders are unable to control or influence the disparate groups within the protest.
"We are urging people intent on attending the protest today or the coming week, to stay away, this is not a safe place. We do not want more people joining this environment and putting their health and safety at risk," a police spokesperson said.
Aggressive behaviour had been directed at both protestors and officers, they said.
Police reaffirmed their stance that the protest site was not a suitable environment for families and children.
Protesters appear to have plumbed toilets into Wellington's sewer system.
A plywood structure next to portaloos at the junction of Molesworth and Hill streets has pipes that go below ground in the centre of the intersection.
Wellington City Council has said the toilets are illegal.
Protesters today have been putting up a similar small building nearby.
Police said they would continue to have a highly visible presence in and around Parliament grounds to reassure residents, businesses and people in the central Wellington area today.
Reporter covering protests tests positive for Covid-19
Stuff's chief political reporter said he has tested positive for Covid-19, after covering the protests outside Parliament for more than a fortnight, at one point having a mask pulled off by a protester.
Henry Cooke said on Twitter this morning he had a positive rapid antigen test (RAT) today after a negative one yesterday.
"Fairly solid symptoms," he wrote, saying that his limbs were aching.
Earlier this month, Cooke said he had a bit of an "altercation thanks to wearing a mask inside the grounds," and a man "reached in behind me and pulled my mask off."
Reporters have faced repeated threats from some of those gathered outside Parliament for nearly three weeks now, and area residents have also reported being abused for wearing masks.