Back In the day we had the police and then a separate lot just for the roads. These days they do target the popular Roads that see a lot off traffic especially On public holidays. The Auckland to Rotorua roads and Matamata section in particular see a lot of enforcement. On the flip side, during public holidays I tend to see less cops on our local roads. One particular trip to rotorua I Spotted 3 camera and a fair few marked units on the road. No tickets in the mail....
The problem now will be some people are scared so will drive significantly slower than the speed limit which will see an increase of dangerous overtaking maneuvers. They have effectively 4 laned the main highway from Auckland to Hamilton now, a modern safe road but still we are only allowed to do 100km/h.