I live in Australia too. Depending the time of the year, during winter, it's correct that in midday, the sun is in the north. However in summer, it's moving closer to south. If you know the east and the west, you can always figure out the north and the south. For example, place east at 3 o'clock, West at 9 o'clock, then north is at 12 and south is at 6. Of course the best is to use compass.