Prime Minister Jacinda Ardern has accused National leader Christopher Luxon of dancing "dangerously close to sympathy" for the Parliament protesters.
Ardern's comments came after Luxon delivered a speech on Monday declaring New Zealand "increasingly divided", which he attributed - among other things - to the Government's COVID-19 response.
"What we are seeing outside Parliament, and the reaction to it, is the culmination of underlying issues that have been rumbling along in our communities for some time," Luxon said.
"It's driven by COVID and vaccine mandates, yes, but the frustrations shared by many Kiwis are also driven by a Government that seems to be stalling.
"The cost of living is through the roof. The dream of home ownership is turning into a nightmare. Long-term benefit dependency is skyrocketing. Then add to the mix Labour's approach to COVID, which relies far too heavily on controlling all aspects of everyday life."
Luxon delivered his speech on the day the protest at Parliament against vaccine mandates and other COVID-19 restrictions entered its third week.
Two weeks ago, when the protest began, police arrested more than 120 protesters after House Speaker Trevor Mallard issued a trespass notice. But a defiant group remained, despite the Speaker's controversial attempts at dispersing them with sprinklers and loud music.
Mallard last Thursday announced a cross-party decision that there would be no dialogue "until the protest returns to one within the law, including the clearing of all illegally parked vehicles that are blocking streets, the removal of unauthorised structures, and the cessation of the intimidation of Wellingtonians".
But the protesters kept coming, with the number of vehicles swelling to approximately 2000 at its peak on Saturday with an estimated 800 vehicles illegally parked near the precinct and tents erected all over Parliament's lawn.
While Ardern has refused to engage with the protesters, describing it as "illegal", Luxon and ACT leader David Seymour have been calling on the Government to provide a vaccine mandate end date.
COVID-19 Response Minister Chris Hipkins on Sunday accused Seymour of "dog-whistling to anti-vaxxers" for suggesting it was time to consider scrapping the mandates.
Luxon is now facing similar accusations from Ardern after his speech.
"All parties in Parliament have said that we will not engage with those who are so blatantly breaking the law in their occupation of Wellington right now, and that was a very clear statement," Ardern said on Tuesday.
"It is a statement that certainly I stand by and we as the Labour Party stand by.
"I don't think that we can move away from such clarity and yet what I saw yesterday from the leader of the Opposition, I have to say, was dangerously close to sympathy for what is happening in Wellington right now.
"It's for him to justify his language but in my view Parliament was right when it stands firmly and collectively in denouncing what is happening on our forecourt.
"There is a place for peaceful protest in this country and many politicians over the years have engaged in peaceful protests. But that is not what is happening on the forecourt."
Luxon pushed back on Ardern's remarks.
"National's position on the protest has not changed - we have not, do not, and will not endorse the protestors' illegal and anti-social behaviour," he told Newshub.
"The actions of the protestors have been intimidating to Wellingtonians and abusive to police. It's been shocking and it needs to stop."
Ardern on Monday denied that her own announcement about when vaccine mandates would be phased out was in response to the protesters.
The Prime Minister said on Tuesday there were "times and places when politics should be put aside and this is one of them".
"What's happening in Wellington is wrong and I don't care which political party you're a member of. I'd like to think that we can all stand together and say, when you threaten people who are working in and around the city, when kids aren't able to move freely, and when it is difficult to just do their jobs in and around Wellington, we should all denounce that very, very clearly."
Her comments came after protesters clashed with police in the early hours of Tuesday for the second day in a row, as officers attempted to reduce the perimeter around Parliament by moving concrete barriers further into areas occupied by the protesters.
A statement from police said some officers were equipped with shields, in order to protect themselves from objects thrown by protesters. Three officers were taken to hospital after being sprayed with a stinging substance.
About 250 police were involved in the operation to shift the concrete bollards. Two people were arrested for obstructing police and one person was arrested for driving in a dangerous manner.
Police said on Monday human waste was thrown at officers while the bollards were being installed. Police were made aware of protesters' plans to again throw human waste at officers on Tuesday.
"The behaviour, the attacks on the police, have been absolutely disgraceful," Ardern said.
"The police are there doing their job to keep Wellingtonians safe, to let them move around the city without being harassed; to have them met with such acts of violence is just totally wrong."
She urged the protesters to go home.
"My message would be to anyone who is down there who believes that they are part of a peaceful protest: that is not what we've seen today. I would encourage them to leave."