Hi BooBoo, yes I seem to remember seeing them in duty free when I was coming back from Fiji earlier this year, but from memory they weren't all that much cheaper anyway. Also (and this applies to the others here who said they had problems with some games from other countries) be careful about buying an overseas version, because it will not play NZ games, and you'll have to import the games from the same region as the console is from. Like DVDs, the Wii console and games are "region locked" so your NZ console will basically only play games bought in NZ.
For those of you who care, that also applies to the Xbox360, but the Playstation 3 has no region locking so you can buy games from overseas with no worries