The absolute best Aussie Online Casino:

Rich Casino - An amazing casino with some of the best slot machines out there. Play Rocky, or other games based on MGM and Marvel comics. Play the Hulk, Iron Man, X-Men and much more. They have millions of dollars in jackpots that are waiting to be won.
You can play in Australian dollars and they offer speedy payments to all of Australia. There's a nice sign up bonus, as well as a great comp program.

Featuring 24 hours a day 7 days a week customer support.

Casino Mate has a great looking website as can be seen below:

Things only get better once you see the lobby: