Opposition to registration is dealt with in Part 5 of the Trade Marks Act 1995 (Cth).
Division 2 sets out the grounds upon which registration may be opposed. They are:
Section 58 – Applicant not the owner of the mark
Section 58A – Opponent’s earlier use of similar trade mark
Section 59 – Lack of intention to use
Section 60 – Likelihood of confusion as a result of reputation of another mark
Section 61 – False geographical indication
Section 62 – Application defective
Section 62A – Application made in bad faith
Note also that section 57 provides that all of the grounds for rejecting an application (as provided by ss 39 to 44) are also grounds of opposition.