Caleb here is the link to:
Find an Answer - Australian Copyright Council
And here is a link to the:
Introduction to copyright brochure
The para in particular you might be interested in is:
How long does copyright last?
Until 1 January 2005, copyright generally lasted for the life of the relevant creator plus 50 years.
There were various exceptions to this rule, including:
• where a work was not published, performed or broadcast during a creatorʼs lifetime; and
• where something was published anonymously or under a pseudonym, and the identity of the creator couldnʼt reasonably be ascertained.
(In each of these cases, copyright lasted for 50 years from the end of the year the work was, with permission, first published, performed or broadcast.)
Under the Free Trade Agreement with the United States, Australia agreed to extend the general duration of copyright. As a result, the rules now are that copyright generally lasts for the life of the creator plus 70 years and where duration depends on year of publication, it lasts until 70 years after it is first published.
The Free Trade Agreement did not, however, include any obligation to revive copyright if copyright had already expired. This means that if, under the old rules, copyright had already expired by 1 January 2005, it stays expired and the material can be used freely under Australian law.