How do you call a toll-free number in Australia from New Zealand?

You can try the call by treating the Australian toll-free number like an ordinary Australian domestic number, prefixing with +61 (from a mobile phone) or 00 61 (from a landline). However, the call may not complete, and if it does you will pay normal international call charges, or possibly more. If the call does not complete, you can try an Australia-friendly VoIP service or look on the web for an ordinary geographic number for the company you are trying to call.