In the US you may be fired for not being able to handle / complete your job duties. These job duties are to be defined before you are hired. If you are able to do your job as it was described to you, then you may have a case for discrimination. If you cannot perform your job function as described to you, or misrepresented your ability to do so when hired, you may be terminated - even if your AS is the primary reason you can't perform your job. I have a fair amount of experience here, actually from the side of the employer, where I have had many employees with developmental or physical disadvantages.
I realize this may not be a great help coming from the other side of the Wrong Planet, but assume Aussie law is at least similar.