Outsourced Medicare payments could be handing companies a "licence to steal" taxpayers' money, one of Australia's leading health finance figures has warned.

Claims processing must be in the hands of public servants who are not motivated by profit, medical billing services pioneer Margaret Faux has written in a passionate defence of Medicare, which, she says, is "too precious to be preyed upon by corporate greed".

The US experience in private billing of public medical services offers a chilling warning of how the private sector can plunder the health budget if given the chance, Ms Faux has written on health blog Croakey.

Plans for a private player to take over Medicare, Pharmaceutical Benefits Scheme and even some Veterans' Affairs payments date back to 2014, and were well advanced until being dumped this month by the Coalition, under pressure from Labor's claim the Turnbull government was bent on full privatisation.

It remains unclear what will happen to the $5 million, 20-strong public service taskforce set up to plan the outsourcing.