You can only register a .com.au or .net.au if you have an active ABN or ACN or a registered trademark or an incorporated association ID.
When placing an order for a .com.au or .net.au you will need to provide one of the above business numbers. An ABN is the most common business number to use.
Also note that a newly registered or a re-activated ABN can take 24 hours to become active. If you place an order for a domain and your ABN is not active we will keep checking the ABN status and will complete the registration as soon as the ABN becomes active. You can check the status of an ABN on the Australian Business Registrar (ABR) website.
You can also check the .au domain administration website auda.org.au for full information about the eligibility criteria of .au domain registrations.
