I doubt you will have any issues with Australian/New Zealand buyers using PayPus - I never have.

It's impatient overseas buyers who think the items will magically transport themselves into their postbox within a few days. When they don't a PayPus dispute is initiated (usually with no consultation to me) and this process is actually encouraged and recommended by PayPus themselves and I see that as part of the problem. Some logic should come in at this point and PayPus should not even allow a dispute to be raised for (say) 30 days after purchase.

The main problem is, to respond to a dispute is very time consuming as well as annoying and in almost all cases completely unnecessary.