The ACMA (Australian Communications and Media Authority) ensures that the Telecommunications (Telemarketing and Research Calls) Industry Standard provides safeguards to enable Australians to manage unwanted telemarketing. These include identification requirements, restrictions on permissible calling hours, and enforcement of compliance with the Do Not Call Register.
You can add your number to the Australian Do Not Call Register, or update your listing, at https://www.donotcall.gov.au/
The ACMA website provides more detailed information on protecting yourself from unwanted marketing calls, and your rights . Two articles that may be of use are linked below.
In addition to listing yourself on the Do Not Call register, you should take advantage of any call blocking features that may be available on your handset to block persistent callers. The manufacturer’s guide will explain how you can activate this feature, or you can use Google to find instructions online for many common handsets. If your handset does not include this feature, consider replacing it with one that does.