Being employed in the shoe department of a popular and despotic franchise that shall remain nameless, allow me to end the controversy.
These 'Australian' sizes you're referring to are 'UK' sizes. Most stores in Australia that sell leather shoes use this sizing system, and the US equivalent is usually one size bigger. That is, a UK/Australian size 7 mens shoe is a US size 8 mens shoe. Stores that sell joggers/runners almost always use the US system.
Now, here's where it gets really confusing. There is no UK/Australian size for ladies, but there is a separate measurement for ladies in the US system. In short, a UK/Australian size 9 is a size 11 in a US ladies shoe.
And no, I don't browse this forum, but stumbled upon this topic from the front page directory. You lucky thing, you.