Reports of private vessels planning to leave Picton with protesters and supplies on board have police and Maritime New Zealand on standby.
It comes on day 16 of the protest's occupation at Parliament, which turned violent yesterday following an early morning police operation to further encircle the demonstration.
Police say a number of people and vehicles have left the protest in recent days, and the offer of free parking at Sky Stadium will end after today.
Greater Wellington's Harbourmaster Grant Nalder says his team are working to ensure anyone attempting to cross the Cook Strait is aware of the dangers and the obligations on them once they enter the Wellington region.
"Crossing the strait is not for the faint-hearted - a degree of experience is needed to understand both the dangers that exist and the obligations of operating a vessel in our region," Nalder said.
"Cook Strait on a calm day is quite nice but if you get it wrong it can be quite unforgiving and we don't want anything to go wrong out there."
"And if they turn up without any thought or forward planning in terms of what they're going to do or where they're going to go, that becomes a problem."
Councillor Penny Gaylor, who is chairwoman of Greater Wellington's Environment Committee said they needed to ensure waters remained safe for all to use and access.
"Our region has had to endure significant disruption because of the actions of some protesters and we don't want that spilling, literally or figuratively, into our waters."
On Monday, a vessel from Picton was pictured delivering protesters and supplies at Wellington's Queens Wharf.
PM - 'Small handful' of people represented at protest
Speaking from the West Coast today, Prime Minister Jacinda Ardern addressed some anti-mandate and convoy protest-related issues.
She said she would not allow a "small handful" of people in the country to command her focus.
She said protesters acting illegally would get no audience with the Government.
One could not hurl human waste at police or abuse local people and then demand talks with lawmakers, she said.
"When you tip into harassment and violence, we cannot condone that."
Meanwhile, police have rejected a new theory circulating on a convoy-related social media site that officers were injured by colleagues rather than protesters in a scuffle on Tuesday.
The Herald asked police about footage circulating which some people say showed an officer holding his face shortly after a colleague set off the pepper spray.
"Police can confirm that a substance was thrown at police by protesters yesterday. The nature of the substance is still being investigated," a police spokeswoman said.
It follows a quiet morning after dramatic scenes unfolded in the capital earlier this week, when police closed in on protesters and set up barriers to restrict any further expansion.
However police responded to a report of a man with a firearm walking in Frank Kitts Park about 7.20 this morning.
Police quickly located the man and found he was not in possession of a firearm, but carrying what appeared to be a taiaha. No further police action was required, and no arrests were made overnight.
Police have also noted a number of people and vehicles leaving the protest at Parliament in recent days, including some who left Molesworth street overnight.
Near the Cenotaph, a woman attending the protest with her son said she came because she opposed mandates and the vaccination of children.
She said she still had safety concerns about the vaccine for kids. She herself was vaccinated but her partner was not. She said the couple just agreed to make a different choice about vaccinations, and they didn't argue.
She said the Government did a great job in 2020 but had recently lost its way.
She said some kids were being excluded from events due to not being vaccinated, and that was wrong.
Free parking ends
Free parking at Sky Stadium will also come to an end tomorrow, chief executive Shane Harmon confirmed, in a decision made jointly by police and the stadium.
The offer of free parking was made early on in the demonstration in a bid to unclog the streets around Parliament.
Sky stadium chief executive Shane Harmon said the scheme had been "partially successful", but it was time to return to normal.
"The 10 days offered has been more than generous on our part and it's time to return to normal."
Police and stadium staff would be onsite to help manage the smooth exit of vehicles.
Human Rights Commissioner Paul Hunt is calling on the government to listen to the protesters, while he is leading a "conciliatory process" un an effort to deescalate the situation.
"If you're trying to repair a stretched and frayed social fabric, you have to listen," he said.
"So we are encouraging the government to find a way to listen to the protesters, with a view to de-escalating the situation."
A meeting held yesterday included representatives from Voices for Freedom and the Human Rights Commission, as well as police, Freedom and Rights Coalition and independents.
Hunt said his duty as Human Rights Commissioner was to "listen, conciliate, educate and advance human rights and responsibilities for all."
"It's clear that the protesters who I have met with have very real stories of loss and suffering. They feel broken and discarded due to the impact of Covid-19 health measures on their lives."
Hunt said some of the protesters had lost loved ones, had had "suffered the side effects of vaccination" or lost their jobs.
He condemned the "outrageous conduct" from some protesters and made it clear he was not affirming their views.
He acknowledged the ongoing harmful impact of the protest but said listening to the protesters was an important step in preventing further violence, as seen in other Covid-related protests overseas.
"In such a heated, fraught moment, we have to move from fear, to hope, and that cannot be done without listening and talking."
The commission, which has faced an unprecedented increased in complaints since the introduction of the traffic light system, recently provided a report on special conditions that vaccine mandates should meet to fulfill human rights requirements.
The conciliation would continue in stages and involve a range of stakeholders, including mana whenua, police, the Commission's chief mediator and Wellington mayor Andy Foster.
Hunt had also asked the Prime Minister to ensure her Government engaged in this "constructive process".
It comes after Wellington mayor Andy Foster defended twice meeting with protesters, saying police had wanted him to do it.
Speaking to Nick Mills on Newstalk ZB's Wellington mornings, Foster said he had now met with protesters twice, with the support of police.
"I got in touch with the police at the highest level and said 'look, do you think this is potentially valuable and helpful' and the answer was 'yes'," he said.
"The police are talking too, and if they didn't think it was worth talking, the police wouldn't be doing it either."
While he respected the Government's decision not to engage with protesters, he said only dialogue was going to resolve the protest.
"We can all stand on the sidelines and say 'please go' but that's not actually going to achieve that, it's only when you're getting in there and listening to people and talking to people when you actually have a chance of getting a result."
Without dialogue he said the only options for resolving the protest were allowing time, or intervening with violence – both of which were unattractive.
He maintained his two meetings had been productive. The first, based around graffiti on the Cenotaph, had resulted in its removal, while the second had focused on reducing the protest's impact on the city.
Foster admitted the protest is made up of diverse groups, and it was difficult to know whether he had spoken to people that could act decisively for the demonstration as a whole.
"It is challenging, and police are finding it challenging to find the people that are going to make decisions … but that's part of talking – if you don't talk, you're never going to know."
He said his meeting with protesters was not legitimising the actions of those that behaved violently.
But Wellington city councillor Fleur Fitzsimmons said the mayor's meeting with protesters sent a "dangerous message" to people who wanted to be heard by government.
"When he met with the protesters, it sent a dangerous message that the violence and the threats and the spreading of conspiracy theories have no consequence, and that that's how you get heard in this city," she told Mills.
"I really don't want that to be the message to a lot of community groups that try really hard to get the attention of the mayor and councillors."
Meanwhile Police Minister Poto Williams said the protests had been "really distressing" for the people of Wellington and particularly for those in close proximity to Parliament.
She backed "100 per cent" the work of police over recent days to minimise the impact of the protest on Wellington, and said the Government doing everything it could to support police.
"The police have been extraordinary, they do put themselves on the line and they shouldn't have to have the kinds of treatment they've been getting," she said.