For Ph.D application, which admission system used in Australia? Is it the same as US/Canada, UK, or EU? Some questions before said that in US/Canada, we should apply first then select the professor and it's different from the system in UK or EU. So, what about Australia or New Zealand?
From my experience in Australia, the usual scenario is that a student makes contact with a particular academic at a university. The academic agrees to supervise the student's PhD. The applicant then applies through the official university process. The university process will involve additional hurdles (e.g., grades, English language requirements, past experience writing research theses, etc.). But in general, the applicant starts by building a relationship with a potential supervisor.

That said, some applicants get in contact with the university with an outline of their research interests, and then the university can facilitate finding a supervisor.

And of course, I'm sure there is some variability in the process across universities. So of course, it makes sense to check out the university websites and get in touch with the HDR office of any relevant universities.