I think Victoria has the greatest number of speed cameras and red-light cameras of any state in Australia. They have both fixed ones (well sign posted and visible) and covert mobile ones. Also note that if you pass road works and the limit drops to 40km/hr, they will often have a camera there to back that up! If you are in an area where you might not see a sign, the default limit is 50km/hr.

On the plus side, there is no pressure anymore to go faster than posted speed limits... when they first introduced 40/km people weren't used to it and you would often find the rest of the traffic banked up behind you or pushing you to go faster (like 45 km/hr). That's now gone, and when it says 40 everyone does 40!