In a statement today, a police spokesperson confirmed a 35-year-old man was arrested inside the grounds in Wellington last night and charged with inciting violence.
He 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 as the protest against Covid-19 measures entered its 20th day.
Police say they are concerned by the deteriorating conditions at Parliament grounds and urged people to stay away from the protest due to "extremely poor" sanitary conditions, aggressive behaviour within the protest group and the presence of Covid.
"Increasingly, key protest group leaders are unable to control or influence the disparate groups within the protest." police said today.
"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.
Police said the number of unwell people amongst the group makes for an unsafe and unpleasant place for anyone thinking of joining the protest.
Aggressive behaviour had been directed at both protesters and officers, police said, and reaffirmed that a protest site was not a suitable environment for families and children.
Toilets plumbed in
Protesters appear to have plumbed toilets into Wellington's sewer system.
A plywood structure next to portaloos at the junction of Molesworth St and Hill St has pipes that go below ground in the centre of the intersection.
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.
Meanwhile, 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 residents have also reported being abused for wearing masks.
