Your current tourist status or a temporary visitor status is not allowed to change to another status within Japan. You first need to apply for a certificate of eligibility at a local immigration office, which is a sort of petition being filed by your employer in Japan as a visa sponsor. Upon the issuance of the certificate you can apply for a working visa at Japanese embassy or consulate office in Australia with the certificate. After your re-entering with a work status and living in Japan for years, you will have a chance to file a permanent residency application. Depending on your status you can apply for PR status after one year to 10 years of stay.
