The brawl between Mongrel Mob and Black Power in Lower Hutt on Sunday is the latest in the area's recent history of violence.
Police believe a gun was fired during the clash in Delaney Park at around 3:45pm yesterday.
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In a Facebook community group, locals say the "gang fight" in Stokes Valley involved shotguns and machetes and claim shots were fired.
"Huge group fighting in the park and over the road," one woman wrote.
"Shotguns and machetes. Quiet now but still wouldn't risk it."
"Keep your families clear," another advised.
One witness said the people involved in the altercation were "all patched members".
Armed police were called out and a cordon put in place. Police have searched several addresses on George Street and say they are "committed to identifying those responsible".
"We want the people of Stokes Valley to feel safe, and we want them to know that violence and the unlawful use of firearms will not be tolerated," says Inspector James Mckay.
It's the latest violence to erupt in the area after a gang shooting in December. Armed police were called to a Hanson St house in Stokes Valley after reports of a man being shot. A 39-year old man was wounded and taken to hospital with moderate injuries.
A witness told Radio NZ that Black Power had been recruiting youths in turf the Mongrel Mob believed was theirs.
And in October a 21-year-old man was shot during a drive-by shooting in Hanson Grove.
In the aftermath, Hutt Valley area commander Sean Hansen told Stuff he didn't believe there was a gang problem in the Hutt Valley, and their presence was "an unfortunate reality across New Zealand".