If you are asking this question from watching a particular episode of the Simpsons, it might justify when you mentioned Australia instead of other southern hemisphere countries. Anyway, this one is not really a new concept, and has been discussed quite a lot in forums and websites, but here's something to help explain things in more detail:
en.wikipedia.org
But the short answer is, the Coriolis effect only applies to large systems, and the apparent observation of water going in particular directions can easily be disproved by putting some dye in the water, and then spinning the water around in the opposite direction. You'll see that the water will then follow that direction, and hence there is no microscopic effect, because this only applies to large systems.
en.wikipedia.org
But the short answer is, the Coriolis effect only applies to large systems, and the apparent observation of water going in particular directions can easily be disproved by putting some dye in the water, and then spinning the water around in the opposite direction. You'll see that the water will then follow that direction, and hence there is no microscopic effect, because this only applies to large systems.