Each Australia State and Territory regulates their own education system, therefore, it is clearly easier to speak of education systems rather than one education system. You can find information in the following links:
Department of Education, Employment and Workplace Relations
or in those of the Department of Immigration and Citizenship
and in Australia Education International
More detailed information on preschool, primary and secondary levels can be found in the States and Territories Departments of Education and Training, as in the Australian Universities for tertiary and higher education studies:
South Australia
Western Australia
New South Wales
Queensland
Tasmania
Victoria
Australian Capital Territory
Northern Territory
Universities Australia