Yes, the largest chunk is students. In fact, ~6% of all international students in the world attend Australian universities, making it the largest per-capita destination for international students by a significant margin. They still require housing, and they still have working rights. Fake students coming over to work without ever attending a class is a well-known rort.

The single biggest justification for our high migration setting (among the highest in the OECD) is ostensibly for skills we need to keep the economy afloat. I've yet to see a skills shortage closed by migration. And of course, skilled migrants are one of the smaller cohorts in our net intake -- we actually bring in more dependents than we do skilled workers.