When Aussies buy gold, they're taking 2 bets, one on the price of gold and the other on the AUD.
The sole reason for gold doing well in AUD is the because the AUD has declined against the USD, if you'd put your money in a USD cash management account since 2010, you'd have been better off with a lot less risk.
Since 2011, gold is down 29%, the USD/AUD cross is up 52%.