Aroha said she was moving to Australia permanently with her boyfriend, Stuart Spashett, also 17.
Friends had started a bonfire in Anderson Park, Mt Albert, after the party supervised by Aroha's mother, Joan.
About 8am, several Black Power members showed up.
"Hard out ! had to use weapons on teenagers. Haha too tough man. They all good, just bruised," one person wrote on Facebook.
Joan Nathan said: "There was no trouble at the party the only trouble she had was after the party."
A police spokesman said there were no reports of any complaints from the area at that time.
Nathan said her daughter was moving to live with her father in Melbourne because there were too few opportunities in New Zealand.