I know the plates have different shapes, but the standard Australia slimline plate fits easilly into the standard european appature, the Japanese plate thing is only an issue on specific JDM imports.
The point is that the plates are not only a shape to fit the appature, they a specifically styled after another juristrictions standard, Australia has its own standards. No other country that I am aware of has plates styled after another jusristriction (Beside NZ and its euro plates. If it was just a matter of shape and size, which is still not really a good reason, there would be no reason to make it appear Euro/Japanense/US whatever. They variety of silly number plate styles in this country is nuts, its anything but a standard.
The craziest thing is people are paying a volentary tax for this sillyness.