If you have multiple cracks appearing on your walls then you should seriously consider covering them up with wallpaper. The mistake that most people make is simply to fill the cracks and then try to cover them up with paint. In nearly all cases the cracks will reappear making this a frustrating exercise.
Australia is famous for having extreme weather but this is probably not news to you. In fact most Australians have grown so used to the dramatic shifts in climatic conditions over the years that they hardly pay any attention to the danger such shifts can pose to their homes.