The Australian Government operates a good overseas student plan - OSP that allows those who are not Australian people or Australian permanent residents to study in Australia.
Anyone who's not an Aussie resident may affect study in Australia underneath the OSP.
If you need to study under the program, you must get yourself a student visa before you commence a span of study in Sydney.
Registered courses
You can be granted a student visa only if you wish to undertake a registered course or part of a registered course on a full-time basis.
A registered course is an education or training course offered by an Australian education provider who is registered with the Australian Government to offer courses to overseas students.
The Department of Education, Science and Training - DEST can provide details of registered courses.