Police have stepped up uniformed patrols in Levin and Foxton to clamp down on violence sparked by a gang power struggle in the wake of the death of Nomads gang leader Dennis "Mossie" Hines.
Molotov cocktails were thrown through a window of a rental house in Levin on Monday night.
Police said the blaze was linked to the shooting of Hines' stepson, Nomads gang associate Tony Cootes, on the day of the gang leader's tangi.
Mr Cootes was wounded in the leg while attending the funeral of Hines in Foxton on Thursday.
Police said there had been five violent incidents, including an assault and a firearms incident, since the death in prison of Hines, the founder of the Nomads in Horowhenua and Otaki.
About a dozen gang members were believed to be involved.
Police have stepped up patrols to curb any more violence and there were no further reports of unrest overnight.
Hines' intention was that upon his death the gang was to disband.
Violence was the result of a leadership struggle and conflict between junior and senior gang members, Detective Senior Sergeant Marc Hercock said.
The juniors were more interested in disbanding than the seniors, he said. Police had received no formal complaint over anything apart from the arson.
However, they were "rigorously" investigating incidents and were taking a zero tolerance to criminal activity, he said.
Mr Hercock said there was no explicit threat to public safety.
"It's within the one gang and it's been limited to gang members against gang members.
"There's no indication that any members of the public are any greater threat than they ordinarily would be."
