The city's biggest private hospitals are not providing their patients with comprehensive price information that can help them budget for simple operations.
This emerged from a recent review by the South China Morning Post, which was conducted after two patients complained about price disputes with their hospitals.
The result echoed an earlier warning from the Director of Audit, which said that "most private hospitals in the city could not provide comprehensive price information for their services", and that the government had been lax in regulating them.
Tim Pang Hung-cheong, a patients' rights advocate with the Society for Community Organisation, called on private hospitals to implement package charges - adding prices to the lists of procedures to be done and facilities to be used.
"Charges in private hospitals are imposed by two parties - the hospital and the doctor - but both have not been clear on their charges," he said.
But Pang said he was not optimistic about the possibility of direct regulation by the government in a free market.
He hoped that the government would improve on public health services so that the private sector would feel the market pressure and adjust their policies accordingly, he said.
Enquiries made through hospitals' hotlines found that only one of the five private hospitals approached could provide a fixed price for simple surgery, such as an appendectomy, while two refused to give even a price range for suturing.
The Hong Kong Sanatorium & Hospital, Baptist Hospital, Matilda Hospital and Hong Kong Adventist Hospital said they could not provide a budget for an appendectomy as the cost varied among doctors.
The Sanatorium said the price disparity between different doctors could come up to as much as tens of thousands of dollars.
The Baptist Hospital said it could give only the standard rate charged for its operating theatre, not including other charges such as surgeon and anaesthetist fees, ward fees and pre- and postoperation check-ups.
Only the Union Hospital provided a package price of HK$35,650 for the surgery.
For wound suturing, the Baptist and Adventist hospitals would not give an expected price for the procedure, only providing the outpatient consultation fee, while the Union Hospital said doctors' charges for the procedure could range from HK$2,000 to HK$5,000.
Medical sector lawmaker Dr Leung Ka-lau, a private doctor, explained that the charges varied according to a doctor's level of experience, the tools used and other factors.
He advised asking the doctor for the expected charge before consenting to having a procedure performed.
Leung also suggested that private hospitals could make public their list of prices for common procedures and items such as the cost of each piece of gauze used.
"When each hospital lists these, patients can compare the prices and make an informed choice," he said.
The Department of Health received a total of 342 complaints against private hospitals from 2008 to 2012. Of those, 58 complaints were related to charge disputes.
But there were no substantiated cases of non-compliance with requirements in respect of transparency of hospital charges, Leung said.
"Most of the complaints about charges were related to doctors' fees, which were not charged by the hospitals, or related to the unexpected increase in fees arising from additional diagnostic tests or emergency services due to complications," a department representative said.
In 2011, the department issued 17 warning letters to private hospitals. But it has never imposed a penalty on any hospital, although it has the power to refuse to approve the re-registration of one.
The Director of Audit's report noted that the regulatory actions taken by the department were not always effective to ensure prompt action by the hospitals concerned.
Discussing the report, the Legislative Council's Public Accounts Committee said it was inexcusable that the department had failed to conducted adequate inspections or to take action against some errant private hospitals.