Stash potato,
I too am a kiwi living in Australia, with an even higher student loan than yours ~100k.
I spent over a year living in NZ trying to earn a decent wage and pay it off. The result? I earned about 18k over about 18 monthss and paid back 1k.
I have been in Australia, earn a ok wage, and am about to pay off another 10k. That would bring my total repayments since moving to Aus at 24k.
Please don't declare bankruptancy, officials back home will point to you, and say "see? This is why graduates shouldn't go overseas, or why we should scrap the system," which makes it harder for everyone else.
Ok so you didn't get a degree, but remember the min wage in Aus is much higher than in New Zealand, and you're not stuck in low end jobs if you don't allow yourself to be. If you get desperate, go work in the mines as a cleaner! I have friends who did that, they kept almost everything they earned, which was decent money, and they didn't need to do it for long.