A new trial of specialist police response teams is set to be rolled out in Counties Manukau, Waikato and Canterbury, manned by members of the armed offenders squad (AOS).
However, it is a move the group 'People Against Prisons Aotearoa' warn could cause "American-style shootings".
Police Minister Stuart Nash said the armed response teams (ARTs) would support police in high-risk situations.
It comes as the threat level in New Zealand remains at medium since the March 15 terrorist attacks.
"Police are continually reviewing the way they respond to high-risk incidents and ensure community safety during critical events. The six-month trial of Armed Response Teams (ARTs) is the latest feature of that ongoing reassessment."
People Against Prisons Aotearoa's Emilie Rākete criticised the move, saying: "It has never been safer to be a police officer in this country, this plan to leave almost 300 armed cops roaming our neighbourhoods will not make anybody safer."
"We know what happens when frontline officers have guns in their hands.
"New Zealanders don’t want our policing to follow the lead of failed approaches overseas. This plan is irresponsible, unnecessary, and will lead to racist violence."
Ms Rākete said the "overwhelming rate of police violence against unarmed Māori" needed to be addressed before "treating the neighbourhoods of the socially deprived like a warzone".
"Māori are currently eight times more likely to be the victims of police violence than Pākehā."
Mr Nash said it was important that frontline police had access to tools and resources during high-risk events.
"The trial of these new teams will be closely monitored and does not mean that Police are moving to routine arming," Mr Nash said.
"Police turn up to some callouts with no knowledge of what they are walking into, every month police turn up to 200 incidents where a firearm is involved.
"Police need to be able to respond in a way that keeps themselves and the public safe. They will carry standard Glock pistols and Tasers and the standard Bushmaster rifles will be in lock boxes in vehicles."
Police Commissioner Mike Bush said the ARTs would be on duty at peak demand times, seven days a week.
ARTs will be "routinely armed, equipped, mobile and ready to respond to significant events".
"Following the events of March 15, police must ensure our people have the tools, capacity, and capability to perform their roles safely and to ensure our communities are, and feel, safe.
The three trial areas were chosen due to having the highest number of firearms seized, located and surrendered, and have the largest AOS groups.
"During the trial, ARTs will be focused on responding to events where a significant risk is posed to the public or staff. They will also support the execution of pre-planned and high-risk search warrants; high-profile public events; and prevention activities," Mr Bush said.