Given the gap in data, the ministry announced on Thursday it would push through legislation to make it mandatory for private hospitals to make public their bill sizes.

While private doctors agree patients should be given the knowledge to make informed choices when it comes to picking a doctor, they argue that price is not the only thing they look for.

Dr Lee Hong Huei, deputy president of the Singapore operations division at ParkwayHealth and CEO of Gleneagles Hospital, said it is not just bill size but clinical outcome that helps patients choose.

'Bill size data should never be the only means for patients to consider. Patients tend to look at specific treatments and the competence of the specialist in delivering it,' he said.

Many specialists say they provide personal and customised care, so 'the difficulty lies in the dictum that there is no 'one-size-fits-all' in health care,' he added.

Professor Tan Ser Kiat, Group CEO of SingHealth and CEO of Singapore General Hospital (SGH), agreed that the clinical outcome of different conditions or procedures should be published in tandem with hospital bill sizes.

'If a doctor is the cheapest in town but his outcome is 90 per cent failure, then...' he said.

Five years ago, MOH moved to make the size of hospital bills public - which triggered almost immediate price cuts at public hospitals that had higher prices than others.

The 11 conditions listed online the private sector contributed to include removal of breast lump, caesarean delivery, Lasik surgery and knee replacement.

These were volunteered by the private hospitals because they are classified under Diagnosis-Related Group (DRG), a system that classifies cases expected to have similar hospital resource use.

'These are carried out by doctors and surgeons working under the private hospitals themselves, making it easier to collate data,' Dr Lee explained.

Hospitals, both private and public, saw 410,000 foreign patients in 2006, 15 per cent more than in 2005.

For instance, foreigners make up as much as 60 per cent of Parkway's patient load while Raffles sees 35 per cent foreigners. MOH said that relative to total patient population, foreigners make up just 2 per cent of the public health-care clusters' patient load, based on hospital admissions.

A spokesman for the ministry said the criterion for 'a meaningful comparison' is that there must be more than 30 cases of a specific condition or procedure for a particular ward class within each hospital in a month.

Reporting by the private sector is of procedures performed by doctors who are part of the hospitals.

But both ParkwayHealth and Mount Alvernia have a second business model where they lease out their premises to individual specialists who run their own clinics and bill them only for the use of facilities and services. But no numbers of such doctors or their areas of expertise were given out by either group.

Since these hospitals are not privy to the fees these doctors charge, they would be hard pressed to churn out the data. Which means there would still be a gap in data unless 'with legislation, the groups managing the medical centres are empowered to know the charges of these individual specialists', Dr Lee said.

One specialist who supports making private medical bills transparent is Dr Jerry Tan, an ophthalmologist in private practice.

'After all, when a patient walks into your clinic, don't you, as the doctor, tell him the price range of the type of surgery he is seeking? Publishing it and making it publicly known is an extension of that,' he said.

Dr Tan added that publishing medical and hospital bills will benefit Singapore's medical tourism in the long run.

'For instance, if a doctor has variable fees to his procedures and gives Indonesian patients outlandishly large bills, you can be sure those patients won't return. It's a no-brainer,' he said.