In corporate Australia, standard business dress is still very much the norm.
Dark suits and ties are the standard dress for management level businessmen with women wearing business suits with either skirts or trousers. (More informal attire is often preferred if doing work outside the major cities.)
Remember that, for much of the year, Australia is a very hot country – so make sure that your clothing is lightweight and cool during those periods.
Try to avoid excessive jewellery and accessories which may be viewed as too flashy and therefore unprofessional.