Fair dealing is a provision of the Copyright Act 1968 (Cth)
that allows you to use a reasonable portion of copyright‑protected material without obtaining permission, provided the use falls within one of the permitted purposes, such as research or study, criticism or review, or parody or satire.
While your thesis is being written and examined, this provision covers your personal copying and quoting from sources.
However, fair dealing for research or study ends when your thesis is made publicly available. Once your thesis is deposited in the CDU Research Webportal under CDU's Open Access policy, the purpose of reproducing the material shifts from private research or study to public communication. You cannot rely on fair dealing as a defence in that context.
This means that any third-party material you have quoted or reproduced beyond an insubstantial amount, and which is not covered by a CC or open licence, must have written permission before the thesis is publicly deposited.