Loaded firearms have been found by officers searching houses in the Lower Hutt suburb of Stokes Valley after a shooting on Saturday.
Police said no arrests have yet been made over the shooting, which left a 39-year-old man with moderate injuries but arrests are likely.
The injured man was treated in hospital and released a short time later.
The detective in charge, Tim Leitch, has reassured locals the police won't tolerate the the unlawful use of guns and they will find those responsible.
A local resident, whose house is on the edge of the police cordon, told RNZ on Saturday that he heard about five shots from a shotgun, with some hitting nearby fences.
He said it was chaos before the police arrived about 20 minutes later.
"There were people hanging around here drinking and then it got a bit serious," he said.
"Everyone just started shouting at each other. There were some people shouting all the way from across the street.
"They just started fighting each other and then it lead to the shooting. Luckily no one else was hurt."
Another witness said there had been tension between the Black Power and Mongrel Mob gangs because Black Power had been recruiting young people in an area the Mob regards as its turf.
Police went door-to-door talking to residents in Hanson Grove.