Yeh it's all state based... Queensland used to let you drive from 16, too, while, the age for L plates (must be accompanied by a full licensed driver) in Victoria used to be 17 up until a few years back, with full license a year later at 18.
Now the law pretty much Australia wide, I think, is 16 for L's, then 18 for P's, then ?21? for full license.
[DRuG]NikT waves his full license at all the green faces.