Canadian police have begun a massive operation to clear the trucker-led protests against Covid health rules clogging the capital for three weeks, with several arrests made and trucks towed away.

Hundreds of heavily armed officers gathered in the early morning on the edges of downtown Ottawa for the start of a gradual clearance process that could take days.

Overnight two protest leaders were arrested and charged with mischief and counselling others to break the law, while this morning several demonstrators were led away in handcuffs as police and tow trucks moved in.

"Some protesters are surrendering and are being arrested," Ottawa police tweeted.

"You must leave," they warned the protesters, telling them "you will face severe penalties if you do not cease further unlawful activity and remove your vehicle and/or property immediately."

Police clearing protesters in Ottawa today

Media were asked to "stay out of police operations for your safety". A police news conference was scheduled later in the day to provide an update.

Demonstrators appeared to dig in after a heavy snowfall, playing cheerful music and waving Canadian flags at the ends of hockey sticks.

The so-called "Freedom Convoy" started with truckers protesting against mandatory Covid vaccines to cross the US border, but its demands have grown to include an end to all pandemic health rules and, for many, a wider anti-establishment agenda.

At its peak, the movement also included blockades of half a dozen US-Canada border crossings including a key trade route across the Ambassador Bridge between Windsor, Ontario and Detroit, Michigan - all of which have been lifted after costing the economy billions of dollars, according to the government.

One of the arrested protest organisers, Tamara Lich, 49, was heard telling truckers as she was being led away by police late yesterday to "hold the line".

The convoy had started with truckers protesting against mandatory Covid vaccines to cross the US border

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Parliament closed

Today, lawmakers took the extraordinary move to cancel a parliamentary session. Speaker of the House Anthony Rota cited "exceptional circumstances" and an "ever-changing" situation in the streets outside the seat of Canada's democracy.

Government workers and MPs were asked to stay away, while anyone already in the parliamentary precinct were urged to shelter indoors.

Police had given protesters a final warning to leave yesterday, as barricades went up to restrict access to the downtown protest zone and surrounding neighbourhoods - encompassing more than 500 acres.

Criticised for failing to act decisively to end the protests and facing pressure from Washington, Prime Minister Justin Trudeau this week invoked the Emergencies Act, which gives the government sweeping powers to deal with a major crisis.

It is only the second time such powers have been invoked in peacetime.

Mr Trudeau decried the protests as "a threat to our democracy"

MPs, split over the move with only a small leftist party backing Trudeau's minority Liberal government, were debating its use when parliament was hastily shut down.

New Democratic Party leader Jagmeet Singh told the Commons yesterday that the protesters were "brazenly" trying to overthrow the government, while accusing the main opposition Tories of "endorsing" the trucker convoy.

Conservative MPs shot back that the government was using a "sledgehammer to crack down on dissent".

Mr Trudeau has said the act was not being used to call in the military against the protesters, and denied restricting freedom of expression.

The objective was simply to "deal with the current threat and to get the situation fully under control", he said Thursday. "Illegal blockades and occupations are not peaceful protests... They have to stop."

Police this week arrested dozens of protesters at border crossings, including four people charged with conspiracy to murder police officers at a checkpoint between Coutts, Alberta and Sweet Grass, Montana.

They also seized dozens of vehicles, as well as a cache of weapons that included rifles, handguns, body armour and ammunition.

Authorities also froze the bank accounts of protesters and chocked off crowdfunding and cryptocurrency transactions supporting the truckers.

New Zealand police reject calls to clear anti-vax camp

Meanwhile, New Zealand police ruled out forcibly clearing anti-vaccination protesters camped around parliament in Wellington on Friday, saying they did not want to provoke violence on the streets of the capital.

Police have taken a hands-off approach after an attempt to take control of the lawns late last week resulted in violent clashes and 120 arrests.

Commissioner Andrew Coster acknowledged growing frustration among Wellington residents and business owners as protest vehicles blocked downtown streets for the 11th day.

But he insisted dialogue with the demonstration's leaders was yielding positive results, even though the number of people squatting outside the legislature continues to swell.

"Enforcement action taken by police runs the real risk of injury to the public, escalation in numbers of people, and a transition away from a largely peaceful protest to violence," Mr Coster said.

"In our assessment, the only safe option at the present point in time is a continued focus on de-escalation."

Police Commissioner Andrew Coster said about 800 people were at the camp, with more than 450 vehicles obstructing roads

The protesters, inspired by Canada's "Freedom Convoy", jammed roads with cars, trucks and campervans early last week, then set up camp on the lawns of parliament.

They have erected tents and shelters, and organised portable toilets, food distribution points and childcare facilities.

New Zealand's largest news website said police had "seemingly ceded control" of the parliamentary precinct, pointing to the presence of protesters acting as self-styled security guards to monitor access to the grounds.

Mr Coster said about 800 people were at the camp, with more than 450 vehicles obstructing roads, and predicted numbers would increase over the weekend.

Police threatened to use the military to tow vehicles this week but backed off after protesters put out a call on social media for reinforcements.

Wellington residents have complained about being abused for wearing masks and noted some far-right messaging among the anti-government and anti-media slogans displayed by protesters.

A group of local mayors, business leaders, unionists and lawmakers issued a statement Friday saying the action had "gone well beyond" peaceful protest.

"The people of Wellington have had enough of this illegal activity, harassment and disruption, we ask that it end immediately," they said.

Parliamentary officials tried to clear the grounds last weekend by playing pop music and children's song "Baby Shark" on a loop and activating the lawn's sprinkler system to soak the camp.