Australia requires that citizens of most countries obtain a visa to enter.  The Australian Consulate General will determine the duration of stay upon receiving an application.
Visa Types:
Short Term Tourist Visa (ETA) – The ETA Tourist visa is for tourists and travelers, and is valid for a maximum stay in Australia of 3 months. To apply for an ETA Tourist Visa, you must also hold a passport from one of the following countries:

Andorra, Austria, Belgium, Brunei, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong (SAR of China), Iceland, Ireland, Italy, Japan, Liechtenstein, Luxembourg, Malaysia, Malta, Monaco, Norway, Portugal, Republic of San Marino, Singapore, South Korea, Spain, Sweden, Switzerland, Taiwan*, The Netherlands, United Kingdom -British Citizen, United Kingdom – British National (Overseas), United States, and Vatican City.

*must not purport to be an official or diplomatic passport

Short Term Business Visa (ETA) – The ETA Business visa has the same validity  as the ETA Tourist visa, being valid for a maximum stay in Australia of 3 months, To apply for an ETA Business Visa, you must also hold a passport from one of the following countries:

Andorra, Austria, Belgium, Brunei, Canada, Denmark, Finland, France, Germany, Greece, Hong Kong (SAR of China), Iceland, Ireland, Italy, Japan, Liechtenstein, Luxembourg, Malaysia, Malta, Monaco, Norway, Portugal, Republic of San Marino, Singapore, South Korea, Spain, Sweden, Switzerland, Taiwan*, The Netherlands, United Kingdom -British Citizen, United Kingdom – British National (Overseas), United States, and Vatican City.

*must not purport to be an official or diplomatic passport

Visitor E-600 Visa – This visa lets you visit Australia to visit or for business visitor purposes for up to three, six or 12 months.