I have just returned from AUS and used Maya mobile. It was easy and required no verification etc. However it uses the Optus network which is not a problem in cities but is not nearly as good as Telstra in rural areas.

Incidentally if the OP is UK based, neither O2 nor 3 work properly in AUS. Data and texts are fine but voice doesn’t work at all. I can’t speak for EE or Vodafone but this is apparently something to do with a recent change in Australian mobile regulations.