The result is tens of thousands more tickets handed out for drivers doing between one and 11 kilometres per hour over the speed limit.
For January 2021, for instance, police figures show static and mobile speed cameras snapped just under 20,000 drivers doing just over the limit. In January 2022, that figure was more than 90,000.
In the first nine months of this year, the number of speedsters caught by mobile cameras had doubled compared to 2021, but fines on average were lower, up by only a fifth.
"This is likely due to changes in camera settings to address road safety outcome risks, resulting in a higher proportion of notices being for offences with lower infringement fees," police told RNZ.
"It means camera activation settings are being set in closer proximity to the speed limit."
What the new activation threshold was, or whether the public were informed of the change, police have not said.
The January-on-January figures for fines against motorists from both mobile and fixed cameras show $600,000 in fines in 2021, and $2.7 million in fines in January 2022.
Police have been under pressure to increase use of speed cameras after years of undershooting the targets that Waka Kotahi/ NZ Transport Agency funds them to hit. NZTA was taking over the cameras next year.
RNZ has asked Police Minister Chris Hipkins if he was aware of the move and if he supported it, given people were paying more fines during a cost-of-living crisis.
In the past couple of years police language has changed around speeding, with its website saying: "Police have the discretion to issue you with a speeding infringement notice (speeding ticket) if you drive at any speed over the limit."
However, officer-issued speeding tickets haven't increased at all in the 1-10kph bracket, only the cameras.
Mobile camera usage hours did not go up markedly in the year either, hitting only 58,000 hours in the 2021-22 year against a target of 80,000-plus.
A motorist caught doing 47 in a 40 zone emailed RNZ on Thursday to say they challenged their ticket, quoting a police manual instruction that advised leeway for speeds up to 10kph over the limit.
"It was rejected with the comment that 'this has not been police advice for a number of years'," the man said.
"My concern is that the police are sending out a large number of speeding tickets for petty amounts over the limit just to make their figures look good.
"As to whether they are actually progressing their objective to majorly reduce crashes and injury and death on the roads by doing so is quite another matter."
In recent times, police have had weekends and holiday periods where they have explicitly dropped the threshold to 4kph.
Enforcement against speeding was central to the Government's Road to Zero strategy that aims to bring death and serious injuries down by 40 percent by 2030.
