Two men have been taken to Auckland City Hospital but their injuries are not life-threatening.
Two people have been arrested for being drunk and disorderly, and interfering with police as they tried to close the situation down.
Senior Sergeant Gary Barber says it's not clear what caused the altercation.
He says it was a confused melee so the CIB is trying to get to the bottom of it.
Gary Barber says at this stage, there's no suggestion gangs were involved.
Two men have been arrested for drunken disorderly and for interfering with police as they tried to shut down the party.