Beyond Blue: post natal depression
http://www.beyondblue.org.au/postnataldepression/
Not necessarily intuitive to find this site. Also not necessarily all that useful, except to blow the trumpet of the government initatives about Post Natal Depression and general depression awareness. Information about support services is relatively easy to find for each state and territory in Australia.
In my experience, half the battle was getting someone to help and actually do something beyond referring me to a psychiatrist. Personally a psychiatrist wasn't the answer; I wanted pro-active things to do beyond someone just listening to my story and yawning at appropriate moments. Now I know the system, I'm better prepared for how to tackle the problem of getting myself listened to. Of course, actually asking for help is half the battle and when the person you ask doesn't bend over backwards to help you get the help you need and you end up chasing your tail through all the different arms of government support, it is far too easy to give up. DON'T! If you think you have a problem, keep telling people until someone points you in the right direction.
In NSW and nationwide, the Dona Maria Pre and Postnatal Support Network is available through a local-call number: 1300 555 578. This services is provided by St John of God Hospital in NSW.
Information for other states, including websites can be found in the Resources section of the Beyond Blue website under Postnatal Depression Information.