There is no problem with re-using a previously used title for a new publication. There is no copyright on the title of publications, so the same title can be used more than once.
If a new edition of an existing title is published it helps avoid confusion by including '2nd edition' on the cover and title page information.
You should also apply for a new ISBN. Information about the Australian ISBN Agency can be found on the National Library's website.
Under the requirements of Legal Deposit you are required to lodge a copy of the new book with the National Library.