In the past his orthopedic surgeon had given him her mobile number in case of a health emergency and now he was using it to call her about money.

The call went to voicemail, so the pensioner chickened out and hung up.

But then the surgeon rang him back. Mr Lonnie, 70, says he quickly explained that he couldn't afford to pay for another hip replacement - the sixth one in his life stemming from a traumatic car accident in his youth.

"She said: 'Don't worry about it??? I've made enough money from you to do this one for free'," he said.

It was a relief. Despite health insurance, Mr Lonnie was anticipating more than $3000 in out-of-pocket fees or having to go on a public hospital waiting list to see a surgeon he did not know.

The former technician had even considered selling his beloved Mazda MX5 to pay for the operation because he trusts his private surgeon so much.

With recent data showing some specialists are charging 15 times what their peers do, leaving some patients up to $10,000 out-of-pocket, a consumer group says patients should investigate fees before they commit to a doctor and haggle if they can't afford it.

"Some people might think it's a bit tacky to negotiate health costs??? but we should all be doing it," said Leanne Wells, chief executive of the of the Consumers Health Forum.

The trouble is, many specialists don't publish their fees on websites, so GPs often refer patients without knowing how much they charge. If a patient wants another referral after seeing that specialist, they often need to go back to their GP and start again.

However, the rise of price comparison websites look set to change this. Several sites publishing specialist doctors' fees have sprung up recently including mind-the-gap.com.au and seekmedi.com.

Health insurers are also pairing up with established health websites such as healthshare.com.au to tell members and their GPs whether a specialist doctor charges their members a fee.

Having recently done a deal with whitecoat.com.au, Chief executive of NIB Mark Fitzgibbon said patients would soon be able to review specialist doctors based on their manner and how long it takes to get an appointment.

Within a year, he said the site would also include patient reported outcome measures such as complications following surgery so members can shop around. For example, Mr Fitzgibbon said NIB would ask patients who have surgery to remove their prostate if they have incontinence or erectile dysfunction a year after the operation so members can compare surgeons' results.

"There can be extreme differences (among surgeons). If I'm a patient facing a prostatectomy, I want that information??? We're working very hard to think about how we can bring this information into GPs surgeries so they can guide their patients on cost information and performance information."

Only doctors who are willing to participate in a "no gap" or "known gap" scheme with the insurer (an agreement where the insurer pays them more, so the member gets charged less) will be on the website. While doctors are fighting the move, Mr Fitzgibbon is confident the insurers will win.

"It gives them marketing reach. Can you imagine a hotel not wanting to be on trip advisor?" he said.

President of the Australian Medical Association Michael Gannon said he was concerned about the validity of complications reported by patients being published on websites and said it could unfairly ruin some doctors' reputations.

"We can't breach patient doctor confidentiality by saying 'that's not true'. It's very difficult," he said.

While recent data revealed about 30-40 per cent of specialist doctors bulk-bill consultations so patients face no out-of-pocket cost, Dr Gannon said Australian Prudential Regulation Authority data showed about 86 per cent of specialist doctors do not charge out-of-pocket fees for procedures. This is despite paying overheads for their businesses such as equipment costs and professional indemnity insurance up to $80,000 a year, he said.

Dr Gannon said although doctors often charged patients less if they fell on hard times, he hoped people wouldn't take advantage of this good will.

"It would be unedifying for professional services to descend to the level of the local bazaar," he said.

But Mr Lonnie disagreed. "If you don't ask the question, you deserve to be fleeced," he said.