Taxi camera footage has been accessed by police in recent weeks to investigate about a dozen complaints.
The Transport Agency says there has been at least one arrest subsequently.
In August, it became mandatory for 6700 taxis in 16 towns and cities to have a working security camera and duress alarm.
The rules were introduced in response to the killings of two taxi drivers who were attacked by passengers.
The Transport Agency says all but one company, which has an exemption, are following the rules and it has not issued any infringement notices.
Christchurch operators are exempted until May.
NZTA says the new rules are making the industry safer by deterring criminals.