Is Australian English closer to US English or British English?
Australian English is quite like British-English. Around WW2, it was very similar, including terms like "pounds, shillings, tea(as in dinner), etc." still in common use. However, during the late 20th century, there is a rise of American English, being now used predominantly in movies, tv shows, etc.
Due to this influence of American English, Australian English is becoming increasingly like American English, as well as several other countries, like New Zealand, Canada, etc. (Not including British-English).