A number of arrests were made overnight in south Auckland after Tongan and Samoan rugby league supporters took to the streets of Otahuhu.
Footage shot by Newshub shows flagpoles and bats being confiscated. Police dogs were used to control the crowd, estimated to number around 3000, which was spilling out onto the road on Atkinson Ave.
Witnesses said fans were picking fights with one another.
Police said 29 were arrested for disorderly behaviour across the Counties Manukau policing area.
Much of the action happened near the corner of Atkinson Ave and Princes St, not far from the Otahuhu Police Station.
Police in Hamilton, where the match was held, made four arrests - mostly for invading the pitch.
"It was a really good crowd, with plenty of singing and plenty of colour," said Insp Karen Henrikson.
Pitch invasions at the tournament are punishable by a fine of up to $5000 or imprisonment for up to three months.
"Police won't tolerate people going onto the pitch and we will charge anyone who is silly enough to do so," said Insp Henrikson.
One person was arrested for intoxication.
Police were also called to an assault on a security guard outside the stadium. The victim was taken to hospital by ambulance, but wasn't seriously injured.
Tonga won the match 32-18.
No arrests were made at the New Zealand vs Scotland match in Christchurch.
"It was a happy crowd of fans who enjoyed the spectacle," said Insp Richard Bruce.