Samantha,
I don't think I'm qualified to answer this ... but I'll take a stab.
First, I think you need to be registered / certified to work in HK.
Places to start include
Department of Health:
http://www.info.gov.hk/dh/main_ser/prof.htm
Email :
http://www.info.gov.hk/dh/email/index.htm
Medical Council:
http://www.mchk.org.hk/
Between these two, they should be able to answer your question on feasibility. There are a fair number of expat doctors in HK from virtually all over the world, so its just a matter of finding out how.
Next, I'd recommend getting in touch with the Australian doctors association. Not sure how helpful they are... but they would know the procedures for sure.
http://www.geoexpat.com/resources/Detailed/62.html
Finally, I'd recommend getting in touch with the Australian Association. They should also be a good starting point for you to find some peers who can guide you through the process.
http://www.geoexpat.com/resources/Detailed/29.html