Drivers in Rotorua have been stung with more than $800,000 in mobile-speed camera fines in the past five years.
But new data shows fewer motorists are getting caught.
Since 2015, more than 10,000 vehicles had been caught speeding by one of these cameras on Rotorua roads.
Drivers racked up $811,150 in mobile speed camera fines but the number of people caught had dropped in the last five years.
In 2015, 4353 Rotorua drivers were snapped speeding compared to only 1313 in 2019.
Comparably, over the same time period, more than 37,000 Tauranga vehicles racked up $2.5 million in fines.
New Zealand Police would not disclose how many speed cameras were used in the Bay of Plenty at any time.
Police operated mobile cameras in vehicles that were deployed to "high-risk crash sites" or places that had problems with excessive speed across the region.
The cameras included a radar system that measured vehicle speed and a flash for night photography.
A police spokeswoman said the drop in camera-issued speed offence notices could be for a number of reasons, including location and deployment through to traffic volume.
She said road safety continued to be a key priority for police and they "remain committed to reducing death and injuries on our roads".
Rotorua Rafting owner Sam Sutton had been a big part of the Okere Falls community rallying for slower speed limits in the area for more than a decade.
The calls were finally heard this year and the New Zealand Transport Agency lowered the speed limits on the stretch of State Highway 33 between Tikitere and Okere Falls.
Since 2009, there had been 120 crashes on that stretch of road. Twenty-six resulting in serious injuries and three involved fatalities.
Sutton said the new speed limit and people abiding by it had made a huge difference to the safety of local businesses and gave him far better peace of mind.
He said although they rafted one of the hardest waterfalls in the country, crossing the road had previously been the "scariest" part of the what they did.
Sutton said they still saw the odd tailgater or people forgetting to hit their brakes down the hill, but otherwise, the change had worked wonders.
"I think we would have received the same result if a speed camera was parked up on the hill."
Hamurana and Awahou Ratepayers and Residents Association's Jennifer Rothwell said police heavily monitored the area as it was well-known for people to speed on Hamurana Rd.
She said police would often sit on the side with the speed monitors or set up camera vans to ensure people did not "hoon" down the road.
The Hamurana community fought to reduce Hamurana Rd from 70km/h to 60km/h a couple of years ago, which Rothwell said had made a difference.
However, there were still "danger spots" in the area, she said, when people went down "much too quickly".
She said they would look at putting further speed reductions on their agenda if the problem worsened.
Last year's road toll in the Bay of Plenty was the highest of any police district in New Zealand, and police have said speed was one of the most common factors.
Static cameras in New Zealand were mostly phased out around the region between 2015 and 2016.
There was only one in the Bay of Plenty on State Highway 2 between Waitahanui Ln and Otamarakau Valley Rd in Pukehina. This was installed in 2018 due to the area being a problem point for speed and crashes and has caught more than 10,000 vehicles speeding.
Road safety charity Brake New Zealand director Caroline Perry said without knowing the number of mobile speed cameras used over this time period, it was hard to know whether it was a "true reflection of behaviour".
However, she said it did "sound promising".
"People reducing their speeds is always what we want to see."
She said most people were "law-abiding citizens" but others "take the risk" for a number of reasons.
It could be ignorance or simply not paying attention, she said.
She said speed usually played a factor in a crash, but more so was a huge part of the outcome. Speed often made the difference between a serious injury and a fatal crash.
"Speed limits are there for a reason."