(From the .auDA website)
Expired Domain Names:
As registrants are made aware when they initially purchase a .au domain name licence, exactly two calendar years after a domain name is registered it will become eligible for expiry. As further explained in the Domain Renewal, Expiry and Deletion Policy (2010-01), if a domain name is not renewed during the renewal period (the period from 90 calendar days before expiry) it will transition from “Registered” to an “Expired Hold” state and cease to function. This means a website attached to the domain name will go offline and any email addresses associated with the name will cease to function.
This state will occur for 30 calendar days where registrants still have the opportunity to contact their registrar and renew the domain name. Failure to renew the name within this period will see the domain name transfer to “Expired Pending Purge” state. In this state a domain name can no longer be renewed, updated or transferred and will be published on The Official Domain Drop List. Exactly one calendar day after the domain name appears on the list it will become eligible for purge and be purged from the registry at the next cycle which occurs at 1.00pm (AEST) or 2.00pm (AEDT). The domain name will then become available for registration on a first come, first served basis.
Deleted Domain Names:
There are two reasons why a domain name is deleted and published on the Official Domain Drop List, either at the request of the registrant or at the request of auDA. Why a registrant deletes their domain name could be for any number of reasons but why auDA will delete a domain name is due to a breach of auDA policy. The deletion process differs depending on whether the domain name was deleted by the registrant or auDA.
When a domain name is deleted at the request of the registrant, the domain name will transition from a ‘Registered’ to ‘Pending Delete’ state at the time the deletion command is submitted by the registrar. At this time, the domain name will be published on the Official Domain Drop List for 3 calendar days after which it will be purged at the next drop cycle.
Domain names that are deleted due to a breach of an auDA Published Policy will transition from a “Registered” to a “Pending Policy Delete” state at the time the deletion command is submitted by the registrar. At this time, the domain name will be published on the Official Domain Drop List for 14 calendar days after which it will be purged at the next drop cycle.
Before attempting to register a domain name that appears on the deleted names section of the Official Domain Drop List, it is important to consider why the domain name was deleted. If the name was deleted by auDA then this would have been the result of a formal complaint being lodged against the previous registrant. In this case, whoever lodged the complaint may have some vested interest in the name and so to prevent having a successful complaint lodged against you for registering the same name, it is essential to assess whether you are in fact eligible for the name and are not in breach of any auDA policy.