Australia is very particular about health insurance, which is why they encourage everyone who is in the country (whether as a permanent citizen or a temporary one, a tourist or a resident) to have comprehensive health insurance.
Except for someone who is a student visa holder, every temporary visa holder can have health insurance from their homeland as well. For students, the health insurance must be given by an Australian provider.
For certain temporary visa subclasses, such as student visa, you will be required to prove adequate health insurance for the entire duration of your stay when applying for the visa, so you will need to apply for insurance prior to visa application.
For all temporary visa holders especially seniors above the age of 75 years, health insurance is strongly recommended each time you visit Australia. The Australian national health scheme (Medicare) will not cover you in case you require treatment unless your home country has an arrangement with the Australian government for reciprocal health care.
If your home country has a reciprocal health care arrangement and you meet the criteria, Medicare will cover you, but only for essential treatment. Most kinds of Dental work, ambulance service, and non-subsidized medicines might not be covered in this kind of insurance.
For further information, please visit the Department of Human Services’ website.