Political opponents of the Mana Movement, and its allies, are calling on leader Hone Harawira to denounce the burning of an Israeli flag during a protest over Gaza at the weekend.
Hundreds of people marched through central Auckland on Sunday, chanting: "Blood, blood, blood on your hands".
Police estimate about 500 pro-Palestinian demonstrators attended the rally. They marched from Aotea Square to the United States Consulate General, where children laid one olive branch on the ground for each of the Palestinians killed.
Photos have been posted online of Mana supporters brandishing party banners, while a United States and an Israeli flag were burned.
Mr Harawira said he understands why Mana supporters were part of the crowd when the flag was burned, saying they're passionate about drawing attention to the ongoing violence against the people in Gaza.
"I'm proud that Mana is standing alongside the people who are being downtrodden in Gaza and opposing the horrible rule that's being visited on them by the people of Israel."
When asked whether he condones the burning of the flag, Mr Harawira said Mana takes a stand in many forms and that he wouldn't resile from the passion that they bring to the stance they take.
He was also asked if actions that could be viewed as extreme may put off potential Mana voters.
"What - burning a flag is extreme? I think killing babies in Gaza is what you call extreme, it's bloody obscene and it's murderous, and I think somebody should be taking steps to stop those bastards from doing it."
The Greens' Global Affairs spokesperson, Kennedy Graham, said he addressed the protesters but did not take part in the march. He saw an Israeli flag with a swastika drawn over it, which he described as hugely inappropriate.
David Shearer, Labour's Foreign Affairs spokesperson, is calling on Mr Harawira to denounce the flag burning, saying he condemns such behaviour. He said he acknowledges that people are passionate, but an important line was crossed.
Maori Affairs Minister Pita Sharples describes the flag burning as really disgusting, saying it's not the New Zealand way.
A former Foreign Minister, and New Zealand First leader, Winston Peters, has a message for those involved.
"You presumably came here because we're a law-abiding, peaceful country that welcomed you. Don't bring your troubles from abroad to this country and think we're going to have violence in the streets as a consequence."
Mana party co-vice president John Minto said the protester who drew a swastika on an Israeli flag was saying that the way Israel was acting towards the Palestinians had strong similarities to the way Nazis reacted towards the Jews in WWII.
He told Radio New Zealand's Morning Report programme right wing Israeli MPs blamed all Palestinians for rockets fired by Hamas and were justifying destruction of the whole community.