At least 10 people have been arrested after more than 100 drunken youths brawled in Napier on Saturday night.
Some were dressed in retro Art Deco costumes, indicating they had been part of this weekend's festivities in Hawke's Bay.
Police say they had to break up fights involving large gatherings of youths in the Marine Parade area. Violence continued to erupt, even with police present, a spokeswoman said.
"Police responded to a number of disorder events in Napier overnight... at least ten youths were arrested.
"There were further arrests across Napier overnight with six taken into custody for disorderly behaviour and four for assault. No serious injuries were reported. "
A witness described the chaos that erupted.
"There's a lot of police and drunken youths knocking about", a Napier man told the Herald.
"Police seem to be pushing them out of town. They were gravitating towards McDonald's but the kids have all done a runner now."
As further reports came in of more fighting, the man said: "The world's gone mad."
Police had cordoned off an area around McDonald's on Thackeray St, the man said.
He hadn't seen anyone being arrested, "but I saw some being grabbed by the scruff of the neck", the man said.
He'd seen more than 100 youths in the city centre during the incident.
Napier's Art Deco runs all this weekend, finishing on Sunday. It draws thousands of people to the city.
The festival delivers over 90 hours of entertainment, along with a huge number of free events which are available for everyone, including the Vintage Car Parade, Great Gatsby Picnic and Memorial Flying Displays.
Earlier, a police spokeswoman said they received two reports of groups of youths fighting in Napier.
The first was in Station St at 8.50pm, when police were told a group of people were fighting and yelling at each other.
No one was hurt, she said.
In the second report police were told at 10.27pm that a group of youths were fighting on Thackeray St.
"[Police were told] it was a large group of people."
The spokeswoman didn't know if anyone had been hurt in the second incident, or if there had been arrests during either incident.
She did not know how many police had attended either incident, but said police were still at the Thackeray St incident at 10.30pm.
It's a busy weekend in Napier, with the four-day Napier Art Deco Festival under way.