Tama Hawkins, Te Rimu Hawkins and Morunga were among them, wearing patches and gang colours.
The court summary stated: "From the moment they arrived, trouble started and small fights broke out."
Guests took cover inside and away from the trouble, fearing for their safety.
A number of serious assaults occurred during the brawl with some people knocked unconscious and the woman celebrating her birthday was stabbed in the back.
No individual offenders could be identified as being responsible for the assaults.
During the fight, a shotgun was presented by one of the uninvited mobsters and fired at least once.
Tama Hawkins' lawyer Scott Jeffersontold Justice Courtney his client was "well thought of by his employer", had no previous convictions and just wanted matters "to be solved".
However, police prosecutor Dean Goodall told the judge the matters surrounding the night were still of "serious consequence".
The judge advised Hawkins to "just get on with your life with no further offending", and sentenced him to 80 hours' community work.
Te Rimu Hawkins was remanded on bail until December 18.
Morunga was remanded on bail until January 30 and as he was escorted out of court by a police officer some in the public gallery shouted obscenities at him.
At least six police officers entered the room to calm the situation before the judge adjourned court.
Officials from Moteo Marae declined to comment.