I think this is how it works if the cops receive a complaint with *555 , it is not a formal report, they will not actually take any action against the driver except:

• Highway patrol might be notified and a lookout notice is posted, if the car is spotted it may be pulled over, the driver breathalysed and the vehicle inspected

• The vehicle owner receives a warning letter from police

• If the complaint is serious you will be asked to hang up and dial 111, in which case again a lookout notice will be posted and a patrol car dispatched to the owner's address

• If you feel particularly vindictive you can complete an online form and formally report the driver, the police will investigate and if they can find CCTV footage of the incident an infringement notice or court summons is issued.

  I have done this twice, on each occasion against police cars I saw speeding (yes I'm a cunt like that), first time I ended up in the Waikato Highway Patrol Area Commander's office, he showed me a big book filled with infringement notices issued against police officers and assured me that they take complaints seriously. It was quite interesting, I was surprised they gave me the time of day.

  Second time, I received a letter of reply telling me that the driver I reported was a detective in an unmarked car, he denied the incident but it was noted on his file (or something like that).

Maybe /u/kiwicop can clarify whether I have it right or not.

Anyway, it's not a bad thing to report to police drivers who are endangering the lives of others. It's not narking, you have no allegiance to other road users. Not only that but in NZ we do not necessarily view the cops as the "opposing side" or "enemy", so reporting an idiot is not seen as narking, it's more doing your civic duty.