The brawl came after days of heightened tension between Samoan and Tongan rugby league fans, ahead of their second round World Cup clash in Hamilton on Saturday.
Police say a crowd of up to 200 Samoan and Tongan fans gathered in a carpark near the Manukau Institute of Technology in Otara last night.
"It was major disorder", said Superintendent Sandra Manderson, the police national commander for major sporting events.
"Some people in the crowd were carrying poles and sticks... I believe there was also a machete taken off someone."
Six people were arrested for disorderly behaviour at about 10pm.
The Samoa and Tonga teams, New Zealand government ministers and police have all appealed for calm after a series of brawls. Police have increased their presence in parts of South Auckland.
Videos posted to Facebook earlier this week showed scuffles breaking out in Ōtāhuhu between supporters holding Samoan and Tongan flags. Four Tongan fans were arrested earlier this week in in Ōtāhuhu and another fight took place on Wednesday night.
Superintendent Manderson said gatherings were being organised over Facebook and social media - some of them simply to show support, such a welcome for the Tonga team at Auckland Airport where 4000 people turned up.
"They were supporting their team.
"The only thing is they're tending to block the roads, which is not okay."
Police were concerned about safety in the lead up to Saturday's match.
"We are worried about [fans'] behaviour on the road... blocking the road, standing on vehicles car-surfing.
"That's of concern to us because we want people to be safe."
Police were meeting daily with church and community leaders and were also engaged with their own Samoan and Tongan police officers, she said.
"We've just had an outstandingly successful British and Irish Lions Tour... there was over 25,000 people came to this country... the people that came over were outstanding, the fans behaved properly. This is not happening here."
Minister for Pacific Peoples and Mangere MP Aupito William Sio said he wasn't impressed with people brawling on the streets of Ōtāhuhu.
"I don't know what it is that these predominantly young men are thinking… but it has to stop. They just need to know it's not okay to fight in public like that. And I think they need to think about the shame they cast on themselves and the good name of their families."
He told Morning Report today he suspected the violence was triggered by a when video surfaced of a young man burning a Samoan flag.
But no-one should retaliate over the "silly prank".
"The boy has apologised, his family has apologised. Let's just focus on enjoying the upcoming game."
The minister said he, Ethnic Communities Minister Jenny Salesa and former boxer David Tua have met with both league teams, and have sent out televised appeals for calm.
Mate Ma'a Tonga has used Facebook to appeal to fans with captain Sika Manu asking them to be respectful.
"We're all from the islands, please keep the peace," he said.
Samoan prop Sam Tagataese called for calm. "From the players' point of view, we call out to both (Samoan and Tongan) fans from both nations to show respect to each other", he told AAP.