Joshua,
In the first link given to you by JoeSixPack, the online medical consultation works very well.
However, please be aware that if you order naltrexone from abroad, then it is HIGHLY LIKELY (as in, virtually 100% certain) that your tablets will not make it past Australian customs. A few countries are extremely, extremely strict, and Australia is one of them. You will likely not have your tablets and lose your money too, because you will not be able to get a refund from either the online company or your credit card company!
I would never suggest to anyone from Australia that they order from abroad for this very reason.
If the Australian online consultation service is not suitable for you, here is a link that gives some very factual and useful information about naltrexone in Australia and how to talk to doctors about it.
http://cthreeeurope.com/2015/03/31/nalt ... australia/