I"ve lived in all 3 of those countries (although have never worked for the police). My experience is just as your friend describes.

The cops in Oz are truly awful! There was a recent scandal where cops were strip-searching teenage girls just for fun. Cops there will also spend more time fining people on bicycles that don't have a bell, than they would in any important crimes.

It differs a bit by state. Apparently NSW and Vic have it worst, although QLD is right up there. Of course in the nation's capital, Canberra, they have the soft ones.