Responding to statistics on offences committed under illegal street-racing law, obtained by The Star under the Official Information Act, the acting southern road-policing manager said the legislation was proving "very effective".
"The legislation does work," Snr Sgt Larking said.
"There is an ongoing problem but I think this has slowed it down," he said.
It is almost two years since the Land Transport (Enforcement Powers) Amendment Act and the Sentencing (Vehicle Confiscation) Amendment Act - legislation specifically targeting street racers - came into force.
The laws empower police to charge drivers and impound their vehicles for an "unnecessary exhibition of speed" or "sustained loss of traction".
Figures obtained from the New Zealand Police show that between December 1, 2009, and September 14 this year 105 vehicles were impounded for street-racing offences in Dunedin.
In the rest of Otago, a further 67 vehicles were impounded.
Nationally, there were 3893 street-racing offences during the same period.
Impounded vehicles are held for 28 days.
Fees for towing and storage have to be paid before the vehicle is released and the vehicles are "green-stickered" - requiring new warrants of fitness before they are allowed back on the road.
"We've found a number of these vehicles have been illegally modified, making them unsafe," Snr Sgt Larking said.
Maximum penalties include a six-month disqualification from driving, a fine of up to $4500, and up to three months' imprisonment.
The costs associated with being being charged for illegal street-racing offences were a "significant deterrent", Snr Sgt Larking said.
"We always have a focus on the boy racer element because we get complaints from the public and because they cause concern for other motorists."
Minister of Police Judith Collins said the laws had successfully sent "a very strong message to illegal street-racers that repeat offending would see the law target the things that mattered most to them - their cars".
Ms Collins said the number of illegal street-racer offences dropped 15% in 2010 compared to 2009.
Offending continued to drop in 2011, she said.
The laws allows vehicles to be seized and destroyed if a driver commits street-racing offences three times.
No vehicles have been destroyed but 17 drivers nationwide have had "two strikes", Ms Collins said.
"When the law came in, I said I would be pleased if no cars were crushed because that would have meant illegal street-racers had changed their ways and the law was an effective deterrent. That seems to be what has happened.
"However, it's always a problem we'll be keeping an eye on and will keep our options open if illegal street-racers go back to their old habits."
