Sorry this is bit of a late reply but just saw the thread.

I work in Job Network (where Centrelink send you to look for work) and as long as your Dr/Ob has your EDD you can be exempt from Job searching requirements 13 weeks (Im pretty sure its 13 weeks, sorry Im going off the top of my head) from your confinement date (your EDD). The Med Cert needs to be on a Centrelink med cert (not just a normal Dr letterhead one) and needs to clearly state your EDD.

Talk to your job network provider if you have any concerns, they can give you more info.

ETA: And I agree with briggsy's girl if your not happy with their decision. You can always appeal it.