Acting road policing national manager Inspector Peter McKennie said "a new fleet of unmarked vehicles will support our ability to prevent deaths and injuries on the road".
The unmarked vehicles will be used to police "high risk" behaviour, including "driving while not wearing seatbelts, driving while impaired, driving distracted, and travelling at unsafe speeds".
McKennie was "unapologetic" if the new initiative meant motorists would stop speeding on the roads.
Motorists will see more Holden Equinox vehicles patrolling the roads over the next three months.
"Police is committed to reducing the number of people being killed or injured on the roads," McKennie said.
"Too many people are losing their lives, and the unmarked vehicles will encourage people to think twice about engaging in risky driving behaviour.
"We want motorists to be conscious about driving safely at all times, expecting there to be a police presence on the roads, anytime, anywhere."
McKennie said the vehicles will come in a range of colours, so they will blend with any other car that is on the road.
"Our officers are out there patrolling the roads every day in an attempt to stop people being killed or injured.
"They are visible across the country in our marked cars, and some are also working in unmarked patrol vehicles, all having a significant impact on making New Zealand roads safer."
McKennie said the majority of people want to get home safely and the increase of marked vehicles will enable police to detect those who drive dangerously, but who slow down when seeing a marked vehicle.
"The vast majority of road users simply want to get through their journeys safely.
"These vehicles increase our ability to ensure that by enabling police to more effectively deter, detect and apprehend those who put people's safety at risk, including those who habitually drive in an unsafe manner but modify their driving in the presence of marked police vehicles."
