Australian rail travellers could rocket from Sydney to Canberra in one hour, a quarter of the current journey time, under a high-speed train blueprint backed by the government.
A bullet train feasibility study said it would cost between Aus$61-$108 billion (US$65-115 billion) to connect the populous east coast with high-speed rail by 2036, when an estimated 54 million people would use it every year.
Trains travelling at up to 350 kilometres per hour (218 mph) could deliver passengers from Sydney to Canberra, the nation's capital, in just one hour, compared to up to four hours now.
Journeys to either southern Melbourne or Brisbane, to the north, would take as little as three hours and at a cost of just Aus$75, said the report, which was commissioned by the government.
Australia's east-coast corridor is currently serviced by air, motorway and regional rail and coach, with train and road trips between Sydney and other major centres taking 10 hours or more.
The Sydney-Melbourne flight corridor is the fifth-busiest in the world and Sydney-Brisbane is the 16th-busiest.
The area's population is expected to boom to 28 million by 2056 and cause significant logjams, with domestic air travel on the east coast and national freight movements set to double by 2030.
Infrastructure Minister Anthony Albanese acknowledged that the cost was "substantial" and the project would service a small population by global standards, but said the government "certainly thinks it's worth it".
Though Australia's land mass is vast, much of it is uninhabitable, leaving its population concentrated in coastal areas. Half of the nation's 22 million people live in Sydney, Brisbane, Canberra and Melbourne.
Proposals for high-speed rail infrastructure in Australia have been under active consideration since the early 1980s, but have never come to fruition.