Members of Tung Chee-hwa's cabinet have been criticised for not going far enough in ensuring their investments do not conflict with their political activities.
An academic and a lawmaker warned that policy secretaries who put shareholdings into family trusts might still manipulate them through relatives.
According to the declaration of top officials' interests disclosed to the public yesterday, Secretary for Financial Services and the Treasury Frederick Ma Si-hang has three companies that are 100 per cent held by family trusts.
Mr Ma says he is not involved in their daily administration, nor does he have any control over investment decisions.
Henry Tang Ying-yen, Secretary for Commerce, Industry and Trade, said he had transferred all his shares in family companies to a trust controlled by his father. 'I am one of the eligible beneficiaries. I do not have the right to give instructions to the trust or the trustees,' Mr Tang said.
The two are among five ministers recruited from the private sector to work in the government. This has raised concerns over previous business links or personal investments conflicting with their public posts.
James Sung Lap-kung, a senior lecturer at City University's School of Continuing and Professional Education, said: 'It would have been better if the trusts were chaired or managed by people with no relations with the two bureau chiefs.'
Albert Ho Chun-yan, of the Democratic Party, said the trusts were 'useless and cosmetic'.
'They [the ministers] can still influence the investment through their family members. It makes no difference if you just entrust it to your father or your wife. You are not seen to be distancing yourself from it,' he said.
Last night Mr Ma's press secretary, Louisa Mak, said Mr Ma had appointed an international trust corporation as the trustee of the family trust.
'All investment decisions and management are made and carried out entirely by the trustee of the family trust,' she said. 'Mr Ma and his family members are not involved in any decision-making and management of the trust assets. The trust will not invest in Hong Kong's listed companies.'
Mr Tang's spokesman said he would not comment further.
According to the declaration of interests, Dr Sarah Liao Sau-tung, Secretary for Environment, Transport and Works, owns seven properties - four in Hong Kong, two on the mainland and one in Britain. Her press secretary said the three companies she had were only for holding property and management of overseas investment.
Secretary for Home Affairs Patrick Ho Chi-ping, who is also an eye specialist, has a business partnership in a clinic, but his spokesman said he had stopped seeing patients since July 18 and had retained the partnership status only for the sake of convenience for his partners.
Lau Siu-kai, head of the Central Policy Unit, owns 50 per cent of a plot in Florida, which he valued at no more than HK$10,000, 50 per cent of a house in Thousand Oaks, in California, and 50 per cent of a flat in the New Territories.
Financial Secretary Antony Leung Kam-chung owns nine properties and 333,333 shares out of 1,333,333 shares of Renful Development (Shandong) Company Limited, a transport-related company which is in the process of winding up.