Are there Mafia in Melbourne?

Yes. In fact, Melbourne is a stronghold of the ’Ndrangheta, the Calabrian Mafia: Honoured Society (Australia). Their main business these days is drugs. They will turn up in the papers maybe once a year.

There was also the spree of Melbourne gangland killings from 1996 to 2010, in which the ’Ndrangheta was only one of six participants. (If only the papers were as clear in their explanations at the time as Wikipedia is now.)