The theses of many Australian universities are available in digital format. Most will be searchable using the resources below and may also be available via library catalogues or an institutional repository.
Libraries Australia - You can perform simple and complex searches, find bibliographic details, locate a library in Australia that holds an item, and follow a number of paths to obtain it. When searching, limit format to Theses.
Trove - Trove accepts all kinds of theses, including honours theses and masters by coursework theses as well as research theses at Masters and PhD level. After searching for a topic, restrict the format to Thesis.
Australasian Open Access Repositories - The Council of Australian University Librarians (CAUL) maintain a list of repository contacts for repositories in Australian and New Zealand universities.