This link takes you to what the process used to be like - bearing in mind, much of the natural justice procedures have  been removed and decisions are generally left with the Immigration Minister to decide. It's written in 2011 but parts of it are still useful to go over.

Refugee and Immigration Legal Service

&

Immigration Advice and Rights Centre

LEGAL INFORMATION KIT*

Visa Cancellation under s501 of the Migration Act

* RAILS and IARC do not guarantee the accuracy of any information contained in this information kit. It contains general information and is not a substitute for legal advice. Visa cancellation under s501 is extremely serious and will result in permanent exclusion from Australia. Therefore you must seek expert legal advice about your specific circumstances as soon as possible if you are faced with the possibility of cancellation under s501.