Officers in Canterbury are expected to stay armed until they have tracked down all weapons linked to violence involving gang members, the Police Association says.
Two men were shot in Kaiapoi, north of Christchurch, early yesterday morning.
Police said they remained in the area today as a scene examination continued.
Frontline officers in Canterbury will be carrying arms as a result of the shootings.
Association president Chris Cahill said that was a serious but necessary step.
"Currently they'll arm themselves until they can identify all those persons that have been involved in the latest incident and recover what firearms they can," he said.
Cahill said firearms incidents had escalated and may continue.
He again called for the implementation of a firearms register.
Legislation passed in June last year which paves the way for a gun register, but Police Minister Poto Williams said in November while work was underway on "firearms licensing and administration", there was no fixed date for any decision, let alone implementation.
Without a registry, Cahill said guns were flowing into gang hands without a trace.
A 23-year-old man and a 31-year-old woman were due to appear at the Christchurch District Court today charged with unlawful possession of a firearm and ammunition after the Kaiapoi incident.