We would need to know what visa you currently hold in order to know your visa conditions and see if you would be required to apply for a new one. Please inform the Registrar that you are already in Australia and forward a copy of your visa so we can check your status.
If you are not from Australia, you will need to apply for an appropriate visa. Details regarding your visa will be communicated upon your acceptance to the school. Please do not apply for a visa until you have received your acceptance letter and instructions to do so.