If you lost your limb in an accident and there is no compensating body, for example at home or during recreation, then the public health system or the National Injury Insurance Scheme (NIIS) will cover the cost of prosthetic limb/s. (Note the NIIS is still a work in progress, funding will be provided by the NDIS in the meantime).
If your amputation was due to trauma such as: a motor vehicle accident or workplace accident, and compensation is identified as a possibility, the Insurance organisation will most likely fund your prosthesis and medical care as part of your rehabilitation needs.
Veterans who either lost their limb as a result of injuries received while serving, or who have a Gold Card, will have their prosthesis paid for by the Department of Veterans Affairs or the Defence Force.
Most Private Health insurance companies do not allocate funding for prosthetics, however it is worth checking with you insurer if you are uncertain as they may cover partial costs.