So, yeah, the specific technicality is that age discrimination starts at 16 in New Zealand (per legislation) so absent a reason to nominate 18 specifically NZBORA is internally inconsistent (and neither the Attorney General nor NZBORA gave such a reason). Given that the second largest party in parliament is opposed to lowering the voting age, this lack of a principled reason (though, perhaps, some are discussed in the judgment, which I haven't read because it's long) strikes me as a weakness given the ball is actually in parliament's court (from the linked article):
A recent law change from Parliament means that any declaration of inconsistency from the courts is put up for special debate.
Tipler said that they are confident the law will change.
“There is a formal process for Parliament to look into the declaration of inconsistency and we are very optimistic that once Parliament reviews the decision they will see that lowering the voting age is the right thing to do.
This optimism seems extremely misplaced in light of a subsequent announcement where it became clear that (1) a 75% majority will be required but neither National nor ACT are for reducing the voting age and (2) that the Prime Minister, Jacinda Ardern, is for change. Frankly, I don't believe Ardern given both my prior analysis (from the old version of this OP, see the link) and that she doesn't clarify whether she'll encourage her own party, Labour, which holds an outright majority of seats in parliament, to vote for change.
So, despite little prospect of change in New Zealand, what say ye, NSG? Should sixteen and seventeen year olds be entitled to vote?
Ironically given my condemnation of the absence of principle (again, the old version of the OP), I hold that the voting age should be tied to the school leaving age... which is 16 NZ. However, I have made an argument there that says it should be fourteen... in a certain sense, if you're entitled to be "home alone" then we have decreed that you are mature enough, responsible enough and capable enough to make decisions absent supervision and therefore you should be able to vote. In NZ, that age is 14.