Six people have been arrested after Waikato party goers spilled into the streets and threw bricks and wood at the police.
Police were called to break up the party of more than 60 people in Huntly at around midnight.
Police said it had spilled into the street with people fighting, smashing bottles and yelling.
Detective Sergeant Dean Anderson said two local police cars had to call for backup as it became too dangerous.
He said when other units arrived the party became destructive with a brick and a rock thrown through police vehicle windows.
Mr Anderson said police had to don riot gear to clear the streets with some officers left bruised after being pelted with bricks and wood.
Six people were arrested for failing to follow police directions, and for breaching the peace and disorder.
One person under 17 also had to be taken home by the police.
