Falling under the current Australia Copyright Act 1968 creators are only allowed to access and use rhythm that is not substantial and has a clear purposes through fair dealing.

Is this correct?

No, this statement is not entirely correct. In Australia, creators can access and use copyrighted material for specific purposes under the fair dealing provisions of the Copyright Act 1968. Fair dealing allows for the use of copyrighted material for purposes such as research, study, criticism, review, parody, satire, and news reporting. However, the amount of material used must be considered fair and not substantial in relation to the overall work. It is also important to note that fair dealing is a flexible and case-by-case exception, and the specific circumstances of each use will be taken into consideration.