There's no "right" answer Kyu... insurance write-offs are different over there, BUT as mentioned above, they're not in the business of giving money away for the sake of it either. So - it's simply a matter of ascertaining in Aussie exactly what happened (ideally visually), and the process it went through to get repaired, who repaired it (and where - Aus or NZ?), and who complied it in NZ.
Of course you must get it properly inspected here by someone who knows the vehicles - and has expertise in vehicle repair... keeping in mind that vandalism may not be simply a cosmetic fix, there's also electronics/coding to consider (which is often where these repaired write-offs fail).
The less information you have, the bigger the risk, and in turn, the lower the price should be... consider the worst case scenario (ie: if your buying privately with no warranty and the car fritzes itself) and whether/how you'd deal with that, however unlikely it is; and then if that price (both purchase and your onsell/trade price) is within your comfort/happy zone - then pull the trigger, it's more likely than not you'll have a happy couple of months/years of ownership. And if not...