NZ has a population of just over 4 million people. These 4 million live in a land area slightly bigger than the UK (80-odd million people).
I recently began to compile a list of all the classes of cars currently racing on our tracks (i.e. excluding rally/off road racing). I got to 26 and gave up-there were a lot I was not aware of. So, with your collective knowledge I will start a list here, beginning with single seaters.
Formula First/Vee
SI Formula Ford
National FF
Historic FF
Formula Libre
Formula Suzuki
Formula Challenge
F5000
TRS
Formula Junior.
Please feel free to add your class or those you know are currently racing.