I'll be visiting New Zealand this December (and taking six segments on NZ, two long ones and four short ones so it's not totally off topic.)

Credit cards in the US all provide insurance for rental cars, and they all have an asterisk saying except in New Zealand. What's the liability when I rent a car in NZ and turn down all of the optional insurance? For that matter, is there optional insurance? Any suggestions? Preferably other than taking the rental car company's over priced this-isn't-insurance insurance? Tnx.