Health Minister Peter Dutton has flagged an overhaul of Medicare, suggesting Australians who can afford it should pay more for their healthcare.

Mr Dutton has used a major speech to declare he wants there to be a frank, fearless and far-reaching discussion about the health system.

He says the current system is unsustainable and he wants to "modernise and strengthen" Medicare.

He has told the ABC's 7.30 program there needs to be discussion around co-payments.

"Commonwealth and state governments contribute 92 cents in the dollar for those treated in the public system," he said.

"Therefore, one important job of the Abbott Government is to grow the opportunity for those Australians who can afford to do so to contribute to their own healthcare costs.

"If they have a means to contribute to their own healthcare, we should be embarking on a discussion about how that payment model will work.

One important job of the Abbott Government is to grow the opportunity for those Australians who can afford to do so to contribute to their own healthcare costs. Peter Dutton

"I want to make sure that, for argument's sake, we have a discussion about you or me on reasonable incomes [and] whether we should expect to pay nothing when we go to a doctor."

There has recently been debate over a proposal to charge patients $6 to visit their general practitioner.

A Commission of Audit, set up by Prime Minister Tony Abbott, received a submission recommending the co-payment system for GP visits.

Under the proposal, pensioners and concession card holders would be exempt from the fee, while families would be granted up to 12 bulk-billed visits annually.

The Australian Medical Association criticised the plan, saying it would discourage people from visiting a doctor when they were sick.

System should 'focus on prevention'

But one of the architects of the Medicare system, Stephen Duckett, says a co-payment is not the way to make the health system more economically sustainable.

"The co-payment is a pimple on a pumpkin," he told ABC News 24.

"It doesn't raise much money.

"It may not raise any money if people go to a hospital emergency department instead."

Professor John Dwyer from the University of New South Wales agrees, saying the nation's health system needs to focus more on prevention to contain costs.

"We've got a terrible burden of chronic and complex disease in Australia [that are] largely lifestyle related," he said.

"Many countries are swinging their healthcare systems around to put the emphasis on prevention, not on sickness, and that's a very cost-effective strategy.

"Medicare needs the infrastructure to move us in that direction."

Labor's health spokeswoman Catherine King says it is becoming clear the Coalition is out to destroy Australia's universal healthcare system.

"Australians who can afford to pay more already do so through a greater contribution to the Medicare levy," she said in a statement.

"What Mr Dutton is really talking about is dismantling our fair and sustainable system in favour of a private health system [as] exists in the United States."

Dutton urges 'bold new ideas' from private sector

Mr Dutton says the private health sector also has a key role to play in making the system more sustainable.

"I believe significant productivity gains can, and must, come through a combination of improved public sector efficiency and bold new ideas from the private sector," he said.

"The private sector has a key role to play to ensure the required productivity gains are realised, including through innovation and technology."

Meanwhile, Mr Dutton has defended his Assistant Minister, Fiona Nash, who is now facing calls to resign.

Senator Nash's chief of staff, Alastair Furnival, quit last week after Labor accused him in Parliament of breaching the code of conduct for his lobbying links.

The Greens are now calling for Senator Nash to stand down, saying she has failed to fully explain the extent of Mr Furnival's links to the food and alcohol industries.

Mr Dutton told 7:30 that Mr Furnival did not have a conflict of interest.

"I knew of course, as everybody else did, Mr Furnival's history," he said.

"As I'm advised, the appropriate declarations were made and signed, and as I say, Mr Furnival has now moved on."