Generally speaking, liberal arts graduates in three years and science graduates in four years. It takes longer to graduate from medicine and other majors.
In addition, Australian universities have a credit system, and graduates get full credits. There are no grades and classes in the university. It is said that only full-time students will graduate in three years, with full credits in each semester and few credits in summer vacation.
If you choose to take more credits in the summer vacation, you can graduate early.