Rupert Murdoch, whilst an Australian, is no longer an Australian citizen. He is now a US citizen and had to take out US citizenship to allow him to buy out Fox. Although News Corp is still based in Adelaide.
The richest man is Kerry Packer -- owner of the Nine Network, Crown Casino, numerous magazine and newspapers - he is also the brains behind World Series Cricket (cricket fans will know what this is and how is came about).
He's also a regular in Las Vegas casinos -- not unusual for him to lose $10 million a night and is from all accounts one of the best tippers out there.
Worth around US$4.5 billion and about 110th richest.
Second richest is Frank Lowry -- worth around US$2.5 billion and is head of Westfield Holdings (shopping centres)