You may not be able to imagine it, but at the time the G4 was released, it was an enormously powerful computer - for tasks that could use Altivec. Remember that the first nuclear weapons were designed with pencil and paper calculations. A G4 could to it quite nicely.
I'm not so sure that you're not part of the axis of evil. You did send us the Crocodile Hunter, didn't you? That was a pretty nasty thing to do. ;-)
Anyway, it was considered reasonable at one time to try to restrict high end computers from export. Shortly after the G4 was released, they raised the level dramatically.
That said, I doubt if that's the issue here. Most countries have safety rules on consumer products. They require certification before the product can be imported. For example, automobiles (at least in the US, presumably in Australia, too) must be shown to meet relevant safety and environmental standards before they can be imported. All electrical products (including computers) must meet relevant electrical standards. Computers must meet specific standards for emission of radio waves. My guess is that the delay is for testing and approval of something like that. Purely routine.