You need to be aware of your rights and quote them to Centrelink staff.
There is a huge difference between Newstart with Exemption and Disability.
Both Dis and NwE require a Job Assessment. Many people with a permanent disability are quite capable of a few hours work so they are automatically being sent to Job Assessment.
Newstart with Exemption requires a doctors cert to say how long you are EXEMPT from work. When I had a broken leg it was a standard 6 weeks - I still had to turn up at Job Assessment on crutches. She ticked the box as exempt and sent me on my way.