A Welsh version of London's Oyster card would bring passengers in Wales greater flexibility, according to an economist.
In a report for the Institute of Welsh Affairs, Will Hutton also suggests a Transport for Wales body to bring more private money to buses and trains.
He argues the organisation could then borrow money against revenue from the smart cards and use this to invest.
The Welsh Assembly Government said it was already rolling out smart cards which could be adapted if required.
In the report, Unpacking the Progressive Consensus, Mr Hutton argues the assembly government takes too restrictive a view of using private money to improve public services.
"Why shouldn't a Transport for Wales collect the fares and, like Transport for London, have borrowing capacity against that publicly owned, but independently gathered, revenue base?
"We would have a non-state institution that would drive a coach and horses through Rhodri Morgan's progressive consensus," he writes.
He argues that the need for increased investment in health and education means more private finance schemes will be needed.
"In turn this means that Wales will have no alternative but to start a debate on the private finance initiative. To think otherwise will be to behave like King Canute in face of the rising tide."
Mr Hutton is the chief executive of the Work Foundation and a former economics correspondent on the BBC's Newsnight programme.
A spokesperson for the Welsh Assembly Government said: "We are rolling out our Smartcard scheme across Wales and are actively looking at ways in which this can be developed further.
"The technology exists for this to be turned into a version of the Oyster Card if we want to go down that route in due course."
The Labour AM for Merthyr Tydfil Huw Lewis has previously called for assembly powers to regulate buses and base it on the London model, which could eventually lead to a Wales-wide Oyster card.
The report is being launched in association with Cardiff University's Wales Governance Centre.