My go to favourite is 'Karen' for the Australian accent. Her voice is far more natural sounding that most of the others I've auditioned, and I use her as the default and pepper all my deployment scripts with 'say' commands now.
She gets 'arvo' and 'stone the crows' right though, so that's something ;-)
https://www.youtube.com/watch?v=Vt4Dfa4fOEY
It's a very strange experience hearing it!
For those that aren’t familiar with Australian vs New Zealand ascents - they’re /very/ different despite how close the countries are physically located to each other. When spoken New Zealand English has more of a British / South African - ‘rounder’ sound, where Australian is generally (especially as you move north or west up the country) more nasal and closer to American English with more emphasis on E rather than O if that makes sense.