You are protected at work from being treated adversely because you have an illness if your employer is aware of your illness.
This means that if you are suffering from an illness or injury your employer has an obligation (under anti-discrimination legislation) to consider making reasonable adjustments (within the capability of the business) to enable you to perform your role.
Your employer might consider meeting with you to discuss what steps the business could take to accommodate your illness at work and make any reasonable adjustments.
Your employer also has a duty to provide a safe workplace for all its employees and to take all reasonable precautions to mitigate any risks. If your illness or injury might be thought to create a risk to yourself or others, then your employer must consider this factor as well.
Sometimes an employer will direct an ill or injured employee to attend an Independent Medical Examination (IME) with a specialist doctor to obtain an opinion as to the employee’s capacity to perform the inherent requirements of their role (i.e. the employee’s job). This applies to both physical and psychological injuries.
There are additional protections if you are on workers’ compensation benefits for your injury (i.e. if you have a compensable injury) however, ultimately if, after a period of time, you are still unable to perform the inherent requirements of your role, then you may face termination.