Before the bidding, analysts had estimated mixed-development sites, which aim to accommodate private and public housing in one development, should bear a 10 to 20 per cent discount to normal private residential sites.

However, it turned out the discount of the Ap Lei Chau site was much smaller than expected, some analysts said.

Chesterton Petty executive director Charles Chan Chiu-kwok said SHKP's bidding price showed the discount of mixed-development sites could be as low as 5 per cent.

He previously expected the Ap Lei Chau lot to fetch HK$600 million.

Mr Chan said the improvement in the property market over the past few months partly explained the higher than expected premium.

The bidding result also reflected developers were keen to undertake large-scale urban projects, he said.

Mixed developments had raised developers' worry that residents paying full market value for homes might not want to share facilities with low-income families.

Judging from the tender result, developers seemed not to be worried about this potential problem, Mr Chan said.

However, the problem will not surface until after such a development is completed and the two categories of residents - one paying full market value for their homes and the other enjoying the discounts - actually live together.

Mr Chan therefore urged the Government not to rush to release mixed-development sites for sale.

Meanwhile, one surveyor said the high premium achieved by the Ap Lei Chau site might reflect only the special characteristics of the district.

Ap Lei Chau was not of a high living standard and had been a mixed area with high-income and low-income people living together, he said.

The tender result might be different for the sale of the 1.49-hectare, mixed-development lot in West Kowloon, he added.

Knight Frank director Anthony Lau said the premium achieved by the Ap Lei Chau lot showed the market had accepted the mixed-development concept.

He believed the Government would gradually release more mixed-development sites for sale.

However, Mr Lau warned it should not base its decision on only one tender result.

On the Ap Lei Chau site, SHKP can build up to 648,000 square feet of residential floor area but has to hand over 194,400 sq ft by random selection to the Government.

The Government will sell the handed-over spaces at deep discounts to low-income families. SHKP can dispose of the remaining space freely.

This arrangement aims to make sure the private and public housing will have the same quality.

It is understood that the Government is still finding a way to deal with mixed-development sites.

It has introduced a new assessment scheme for the West Kowloon site, due to close for bidding on April 28.

For this site, the Government will emphasise quality.

Under this scheme, developers' bidding prices will be weighted by an equation where the highest bidders will be given 50 marks. The prices of other bidders will then be divided by the highest bidding price and multiplied by 50.

This way, if the second-highest bidding price is 10 per cent lower than the highest one, the bidder will get 45 marks. If it is more than five marks ahead of the highest bidder in quality terms, it still can win.

On the quality front, the Government will assess the overall planning, design and management of the development. The perfect proposal will score 50 marks.

Under the marking scheme adopted for the Ap Lei Chau site, bidders who score lower than 50 out of 100 for their proposal's quality cannot proceed to the second stage of the assessment, in which only premium will be considered.