The minister said that when the government allowed a private business to build and run public services it needed to ensure that the public are not charged unreasonably high fees.

She cited the government's failure to have the Western Harbour Crossing cut its fare as a classic case of a private-sector participated project carried out without a proper regulating mechanism.

Chief Executive Tung Chee-hwa vowed in his policy address in January that Hong Kong would make wider use of alternative approaches, such as public-private-partnership, in carrying out large-scale public works projects.

'The government is actively reviewing and exploring possibilities to deliver the public works projects managed by the Works Departments through alternative approaches, such as public-private-partnership, with a view to bringing about more benefits to both government and the public,' he said.

Last April, Secretary for Home Affairs Patrick Ho Chi-ping launched two projects with private sector involvement. They include an ice-sports centre in Tseung Kwan O, as well as a leisure and cultural centre in Kwun Tong, with a total value of $2.5 billion.

Financial Secretary Henry Tang Ying-yen said in his budget speech last Wednesday that the government would expand its public-private sector partnership programme, saying a consultancy study had been completed on whether the new model could be adopted in the $6 billion redevelopment of the Sha Tin water treatment plant.

But Dr Liao said a more co-ordinated approach was needed in carrying out such projects.

'Our bureau is now acting like an agent. When other government departments decided that certain projects should adopt the public-private-partnership approach, we will make it happen. I believe we need to work out how it can be monitored. The debate certainly should also involve Legco,' the minister said.

Under the public-private-partnership model, which is widely used in Britain, Australia and New Zealand, private firms can be enlisted for the financing, designing, building and managing of public facilities. In return, private business pockets the income generated from the public facilitates.

At present, there is no regulating mechanism on what projects should be allowed with private sector involvement. Since no funding is required from Legco under the new approach, lawmakers' approval is not needed.

Anthony Cheung Bing-leung, a public administration specialist at City University, said it was inevitable Hong Kong adopt this approach as it allowed a government seeking to reduce expenditure to continue providing services to the public.

But he stressed it would be essential for the government to strike a balance between attracting private business and protecting public interest. He also urged the government to inform the Legislative Council on public-private-partnership projects in the pipeline.

He cited the controversial West Kowloon cultural district project, in which the government decided to let a private consortium construct the 40-hectare waterfront site and manage it for 30 years, as a case study of public-private-partnership.