Watch: Anti-mandate protester shoulder-charges police officer, knocking them to ground

A video circulating online shows a protester shoulder-charging a police officer and knocking him to the ground as the turmoil at Parliament continues. 

Anti-mandate protesters have been occupying Parliament's grounds for more than 16 days with violence erupting on Tuesday. Three officers were hospitalised after having an unknown stinging substance thrown on them while a man was arrested after trying to drive a car into police. Frontline officers were also forced to use riot shields after protesters threw human waste on them on Monday. 

Tensions also erupted on Wednesday night between police and protesters when demonstrators removed a concrete bollard near Parliament to let more cars in. 

Demonstrators claim as many as 30 car managed to re-enter the area.

And while the violence has settled down since then, videos online continue to show police being subjected to violence and harassment. 

A video being shared on Twitter shows a man running up to a group of police officers before knocking one onto the ground. The officer falls onto the sidewalk and the man responsible runs away. 

It comes as nearly 140,000 people have signed a petition calling for the protesters to go home. 

The Change.org petition says New Zealand is witnessing a "takeover of democracy" similar to the Capitol riots in the United States last year.

"[They are] a disparate group of conspiracy theorists, religious cult members, anti-vaxxers, anti-mandate believers and flat earthers," the petition says.

The petition was started after reports of locals being spat on, having their masks ripped off and even being assaulted. 

Police have also been accused of violence, with one protester claiming he was eye-gouged and punched during Tuesday's violence.

A series of videos taken during the early stages of the anti-mandate protest also called into question police claims of "professional" conduct while dealing with demonstrators.  One showed what appeared to be a naked woman being dragged by her dreadlocks out of a stand-off between police and protesters.

Prime Minister Jacinda Ardern has repeatedly refused to engage with the protesters instead telling them to go home. While National Leader Christpher Luxon called their behaviour "totally and utterly unacceptable". 

The police have also condemned the violence with Assistant Police Commissioner Richard Chambers saying it was "disgraceful and unacceptable".

In a statement on Thursday, police said they are concerned by the "level of aggressive behaviour from protesters". 

"Last night protesters on Hill Street armed themselves with makeshift shields made of plywood and rope, although the Police presence was to manage the cordon. Police are collecting evidence of unlawful behaviour for further follow-up and possible prosecution.

"At about 4pm yesterday a group of 10-15 protesters entered Pipitea Marae and demanded Police and Māori wardens vacate immediately. The group were verbally trespassed by police."

Police said the number of protesters is declining with between 150 to 300 people at different times of the day. 

"A visible presence remains at Parliament today as police continue to monitor protest activity and plan to further reduce the cordon over the coming days as we return freedom of movement to Wellington."