Domain names in the .au namespace have strict requirements around who is eligible to register them. The requirements for .com.au and .net.au domains are detailed here.
.COM.AU & .NET.AU Eligibility requirements
In accordance with Australian Domain Name Policy, to be eligible to register .com.au or .net.au domain names, registrants must be one of the following:
- An Australian registered company
- Trading under a registered business name in any Australian State or Territory
- An Australian partnership or sole trader
- A foreign company licensed to trade in Australia
- Be an owner of an Australian Registered Trade Mark
- An applicant for an Australian Registered Trade Mark
- An association incorporated in any Australian State or Territory
- An Australian commercial statutory body
Domain names in the com.au or net.au domain space must:
- Exactly match, acronym or abbreviation of the registrant's company or trading name, organization or association name or trademark; or
- Be otherwise closely and substantially connected to the registrant.
If you don't know your ABN/ACN, you can find it here.