Australian state and territories could save $15.5 billion if they followed Victoria's lead and let private business run public transport.
Infrastructure Australia says between $11.6 billion and $15.5 billion could be saved by 2040 if private business was at the helm of train and bus services in Sydney, Brisbane, Melbourne, Adelaide, Perth and Canberra.
Victoria's Kennett government privatised operation of Melbourne's trains and trams in 1999.
But a Victorian transport union says the report released on Friday focuses on money, instead of service.
"Its only true consideration is the bottom line - not customer satisfaction, not service reliability, not safety," Rail Tram and Bus Union Victorian secretary Luba Grigorovitch told ABC radio.
"Public transport is a public service like our hospitals and schools and we expect the government to guarantee the level of funding and services, as many of us depend on this service every day."
Most of Infrastructure Australia's estimated savings come from NSW ($6.7-9 billion) and Queensland ($2.5-3.4 billion), where the majority of Sydney and Brisbane's trains and buses are publicly-run.
