The general protections of the Fair Work Act render it unlawful for an employer to take adverse action against an employee, or prospective employee because of the persons physical or mental disability.
Here is an extract from a recent decision of the Federal Court of Australia which discloses that this is not as simple as it sounds. You be the judge.
“The term “disability” employed in s 351(1) includes the “manifestations” of that disability: Shizas v Commissioner of Police FCA 61, (2017) 268 IR 71 (“Shizas”). In the context of considering a “physical disability”, Katzmann J there concluded (at 95 to 96):
 But the question here is not whether a condition and its manifestations may be disaggregated; it is whether a particular disability can be severed from its manifestations. With the greatest respect, absent a statutory definition to that effect, which is missing from the [Fair Work Act], I have real difficulty with the notion that “disability” can ever exclude the manifestations of a condition. In the absence of a statutory definition, one must look to the ordinary meaning of the word. In its ordinary meaning “disability” denotes both the condition and its manifestations. …
 In any event, it would be “difficult, if not artificial” to draw a distinction between ankylosing spondylitis and its manifestations. To say that a person has ankylosing spondylitis is to say that he or she has, or may be susceptible to, problems of a particular kind with his or her spine and related joints. The relationship of a disability to its manifestations is not one of cause and effect; it is between a label and the things to which the label refers. Ankylosing spondylitis is “a chronic inflammatory rheumatic disorder”, primarily affecting the spine. Its hallmark is sacroiliitis (inflammation of the sacrum) accompanied by inflammation of the entheses (the points of union between tendon, ligament, or capsule and bone) and formation of syndesmophytes (bony growths originating inside a spinal ligament), which in the later stages of the disease lead to spinal ankylosis (or fusion).
Her Honour continued a little later as follows (at 97):
 The Commissioner rightly accepted that the burden is on the employer to prove that adverse action was taken because of the inherent requirements of “the particular position concerned”. Although the exception in s 351(2)(b) does not come within the terms of the reverse onus provision in s 361, it is highly unlikely that Parliament intended the onus to lie with the employee to prove the negative, particularly in relation to a matter such as this that would be peculiarly within the knowledge of the employer.
 In determining whether the Commissioner has discharged his onus of proof it is first necessary to identify “the particular position concerned”, and then to determine whether each of the two decisions was made because of the inherent requirements of that position.”
See also: RailPro Services Pty Ltd v Flavel  FCA 504 at , (2015) 242 FCR 424 at 459 per Perry J.
Robinson v Western Union Business Solutions (Australia) Pty Ltd  FCA 1913(30 November 2018) (Flick J)