Private hospitals and doctors would have to tell patients the likely cost of their treatment in advance under a law the government plans to introduce this year.
This would help patients to better estimate their medical bills and make comparisons between providers, and reduce disputes.
It would also pave the way for government reform of medical insurance, which aims to encourage more Hongkongers to use private health care, easing the burden on overloaded public hospitals.
The costing proposal is expected to be introduced by the Food and Health Bureau in the second half of this year, the South China Morning Post can reveal.
"There are still more details to be formulated under the new bill," a source familiar with the issue said.
The plan comes a year after the Audit Commission criticised most private hospitals for not giving patients enough price information before treatment. It also said the government was lax in regulating them.
Unlike public hospitals which have standardised pricing, private sector bills are decided by two parties - the hospital and the doctor. A bill can vary significantly according to the doctor's level of experience, the equipment used and other factors.
This makes it difficult for private hospital patients to budget for their treatment and has led to disputes. Between 2008 and 2012, the Department of Health received 342 complaints against private hospitals, 58 of them related to price disputes.
Under the government proposal, both private hospitals and doctors would be required by law to offer a clear estimate of medical expenses to patients before giving them treatment.
The government is still considering several factors, such as whether hospitals and doctors should be allowed to give just a price range instead of a precise figure, and if so how wide the range should be and whether there should be any exemptions.
The source said the bureau favoured Singapore's model, which required private hospitals to give patients two bill estimates. One is the median, meaning 50 per cent of patients will pay more and 50 per cent less. The other, meant to illustrate the upper range of bills, is an amount only the top 10 per cent of bills will exceed. This covers more than 70 common medical procedures.
Only two of Hong Kong's 11 private hospitals - Union Hospital in Sha Tin and St Teresa's Hospital in Kowloon City - now offer such information in advance.
Legislator and private doctor Dr Leung Ka-lau said he was open to the idea but worried the law might be difficult to enforce, as medical treatment often involved unexpected procedures.
"People who propose the idea should also suggest a way to accommodate these unexpected procedures," Leung said.
Tim Pang Hung-cheong, a patients' rights advocate with the Society for Community Organisation, called on private hospitals to implement a set of fixed- package charges.
The government source said the bureau would continue its efforts to encourage more private hospitals to set fixed prices. The new Gleneagles Hong Kong private hospital in Wong Chuk Hang - to open in 2017 - will offer fixed prices for half of its services.