I'm a Canadian who was in Melbourne for a few months and I met a guy there who had been initiated into Kappa Sigma Fraternity. (He was technically English not Aussie, but he lives in Melbourne now).
Yes, fraternities do take international students, but you should know that there is more to fraternities than drinking and partying. You will be expected to maintain a decent GPA level, pay dues and participate in philanthropic activities.
If you want to look into this website...here is a good spot to start, the homepage for the National Interfraternity Conference:
http://www.nicindy.org/joining.htm
Good Luck!