A big jump in the number of speeding tickets being issued has placed the police in familiar territory. They are having to defend the enforcement of speed limits as if it was either some sort of whim or simply a money-making exercise.
"We're not interested in revenue, we're interested in safety," said Superintendent Paula Rose somewhat plaintively. The national road policing manager could afford to be a little more assertive. Road toll statistics for the past few years provide her with more than enough ammunition to suggest the police are on the right track.
Ms Rose attributed the 627,948 tickets handed out for speeding infringements last year - up from 329,838 in 2009 - to three factors.
These were the introduction of digital speed cameras, the better deployment of police resources, and reduced speed tolerance during holiday periods.
In sum, the police have been more efficient in apprehending those who don't obey the legal limits and place other road-users at risk.
The trend has continued this year. In the first four months, the country's 55 cameras captured 200,671 incidents of speeding.
This has drawn a one-dimensional response from the Automobile Association, which suggests fixed speed cameras should be painted brightly and signposted in the areas where they're operating.
That rather misses the point, which is to encourage motorists to stay within the speed limit at all times.
It also flies in the face of road toll statistics that indicate the cameras are a valuable tool in enhancing safety. At the end of August, 188 people had died on New Zealand roads this year, 66 fewer than at the same time in 2010. That represents the lowest eight months since monthly records began in 1965.
It's also worth noting the greater police emphasis on speed follows a horrendous Easter holiday period last year, when 12 people died. It's estimated speed contributes to a third of all fatal crashes.
Notwithstanding all this, the AA also chose to stir the embers of opposition to speed cameras by pointing to a public perception that fines are simply "revenue gathering". It would have been rather more responsible to state that the threat of a fine causes drivers to take their foot off the accelerator, and this leads to fewer accidents.
It is true, however, that to keep the vast majority of people on side, the police should use cameras discreetly. They should be located in accident blackspots, where speed is normally a factor in crashes, rather than on safe stretches of road.
Ms Rose says police resources are now being better applied to areas of risk. This must continue if those wishing to incite public objections are to be denied a valid argument.
The AA's road safety manager also suggested the more tickets being issued by the police, the more the system is failing. "The best speed camera is one that doesn't issue any ticket," said Mike Noon.
That, of course, is everyone's ultimate goal. When motorists show a readiness to stay within the speed limit without the threat of penalty, the cameras' job will be done. But, while progress has been made in several other areas of road safety, not least drink-driving, speeding has remained a vexed problem in this country.
In too many instances, drivers still have a scornful disregard for the speed limit. Cameras alone will not improve this attitude. Part of the solution also lies in smart education campaigns and a strong police visibility on the roads.
But the police should be doing everything in their power to improve motorists' behaviour. For some time speed cameras will be an integral part of this for the simple reason they save lives.