As I understand it, the reason why it is said that homebirth will be illegal is this:
At the moment there is an exemption which allows a midwife to attend a homebirth without insurance. When the exemption expires, my understanding is that under the existing rules it will be illegal for a midwife to practice without insurance (it is a requirement of registration to have insurance). However, it is not currently possible for a midwife to obtain insurance that covers attendance at homebirths. Hence the catch-22. When I last asked the DoHA about this (in September 10) they said it was 'currently under discussion' but query whether that is actually true or just a standard answer.
It is theoretically possible that obstetricians or GP obstetricians may enter into collaborative agreement which allows midwives to attend homebirths but it is not clear how this would work exactly - what kind of 'supervision' would be required from the OB, and whether the OB's insurance would cover the homebirth. It doesn't seem that likely to me, as it would probably result in a large loading of premium that the OB/GP OB would have to bear, so at the moment I am not sure how they will get around this.