Detective Sergeant John Hedges, of Dunedin, said the weapons were found concealed in cars and on gang members during gang-related incidents recently attended by police in Dunedin.
"We are alarmed at what we have found. Carrying weapons is becoming routine.
"It is a Mongrel Mob problem. They are patched up, in town and causing problems."
Weapons found included a machete, sawn-off shotguns, numchukas, a crossbow, screwdrivers, knives, baseball bats and pieces of household furniture shaped for use as a weapon.
Often, the weapons were found under car seats, or up a gang member's sleeve.
Det Sgt Hedges agreed the weapons found would be the tip of the iceberg, but said police would continue to stop and search gang members, seize weapons and lay charges of possessing an offensive weapon.
In the latest gang incident, a fight broke out between the Mongrel Mob Aotearoa and Black Power outside the Dunedin courthouse.
About a dozen police officers and courthouse security staff joined forces to arrest two men on the street after gang members began fighting about 10.30am.
Witnesses said the gang members were pushing and punching each other.
Senior Sergeant Craig Brown, of Dunedin, said court staff had accidentally scheduled cases involving both gangs yesterday.
Two Black Power associates appeared in the Dunedin District Court in the morning - one appeared on a family violence matter and the other, Allan Waru Kukutai (31), of Henley, on a charge of unlawfully having an offensive weapon (a broken broom handle), which he had allegedly used to attack a Mongrel Mob member in Brockville Rd on Wednesday.
Mongrel Mob member Garth George Warren Tairi (35), of Mosgiel, was also in court yesterday charged with possessing cannabis.
Ministry of Justice senior corporate communications adviser Phil Barclay said courts would schedule proceedings so that known members of gangs were not at court at the same time.
However, even with the best of intentions, circumstances sometimes arose when this was not possible.
"Courts balance a number of legal principles and practical matters in scheduling appearances. The main one is that people held in custody must be brought before the court as soon as practicable.
"Scheduling appearances so that gangs don't meet at court also depends on knowing who is a member or associate of which gang. When we know, we schedule accordingly."
Snr Sgt Brown said two Mongrel Mob members were arrested after yesterday's incident outside the court.
One was charged with disorderly behaviour likely to cause violence and resisting arrest, the other with unlawfully interfering with a vehicle owned by a Black Power member.
"Members of both gangs turned up to carry on the intimidatory tactics that have been going on over the last few weeks in the city.
"They are obviously not learning quickly, but rest assured, they will learn. We are not going to tolerate their violent or intimidatory tactics," he said.
