You need an ETA for United States if you have an Australian passport

Travelers need a travel authorization to visit United States of America for Business or Tourism. The Electronic System for Travel Authorization (ESTA) is an online application that determines the eligibility of visitors to enter United States. Once the application is approved, travelers receive their ESTA confirmation electronically. A valid ESTA is required to visit the country. If the ESTA is expired or doesn’t match the traveler’s passport information, travelers will not be able to board their flight. An ESTA is electronically linked to a passport and valid for 2 years. If travelers receive a new passport, they must apply for a new ESTA. United States permanent residents or holders of valid United States visas don’t need an ESTA. Travelers who visited Cuba on or after January 12, 2021, are no longer eligible for an ESTA and must apply for a visitor visa to enter the United States. Travelers who visited Iran, Iraq, North Korea, Sudan, Syria, Libya, Somalia and Yemen on or after March 1, 2011, are no longer eligible for an ESTA and must apply for a visitor visa to enter the United States. Different requirements may apply to travelers who have visited these countries for diplomatic or military purposes. For further details on exceptions, please review the government website.