The latest published postcode map to cover all of Australia was the Official Australian postcode map which was produced by the Australian Surveying and Land Information Group (AUSLIG) in 1993. This map is still under copyright, which is held by Australia Post, and by now much of the information on it is out of date. If you wish to obtain a copy of this map from the Library, you will first need to contact Australia Post to obtain their permission.
While there has been no Australia wide map produced since this one there have been paper maps for some individual states produced by commercial and state government publishers. For example,