Using cameras mounted on the roof of the patrol vehicle, the ANPR system scans the number plates of passing vehicles and feeds the information to a computer inside the vehicle.
Mr Fagan said Northland's unpredictable weather had not hindered the effectiveness of the equipment and the ANPR system operated equally well in rain or fog, day or night.
"This vehicle will be deployed across the Northland Policing District with the possibility of a second vehicle being available for operations by our Commercial Vehicle Investigation Unit."
The ANPR unit only captures the number plates of those vehicles that are of interest to police, such as those that may have been ordered off the road or are otherwise unsafe, or that have been used in crime.
Police said it did not capture personal information about drivers or passengers, and operated without disrupting law-abiding road users.
The technology simply automates a process police normally have to do manually via an officer calling a radio dispatcher - and accesses information that police already hold.
Mr Cliff stressed the technology was vehicle-focused, so average law-abiding road users have nothing to worry about.
The units cost $35,000-$40,000 each, including installation into the vehicles. Depending on traffic flow, the ANPR unit is capable of scanning up to 3000 plates in one hour.