HONGKONG Bank has called on the Government to make more land available and allow the import of more labour for the construction industry to ease supply bottlenecks in the property market. ''In the next couple of years, an improved balance between supply and demand is expected to bring greater stability to the market,'' the bank says in its latest economic report. ''However, with the possible exception of industrial property, all sectors are likely to be overshadowed by the large supply projected to become available.'' ''To ensure stability in the longer term, Government must ease the supply bottlenecks by making available sufficient supplies of land and an adequate quota of imported labour for the construction sector.'' Another influential body, the Asian Development Bank, recently said the Government would need to at least double its 25,000 worker ceiling on annual labour imports to ease Hongkong's chronic labour shortage this year. Hongkong Bank was less specific, but said the already tight construction labour market could tighten further over the next few years given the demand for labour on port and airport projects. The labour shortage was one factor preventing an oversupply in the property market. Another was the strong financial position of developers and property owners which allowed them to delay sales in a depressed market. ''On the demand side, given the prospect for persistently high inflation and low interest rates, strong demand for properties is expected to continue, supported by sustained economic growth and the expanding role of Hongkong as a gateway to China,'' the report said. ''An increasing number of local and foreign companies are likely to set up offices in Hongkong to handle business associated with China and the port and airport development projects, suggesting that demand for office space will increase.'' Rising household income and a surge in the number of residents of home-buying age would fuel demand in the residential and commercial sectors. The bank said the affordability ratio of residential property had improved ''to a more comfortable level'' by the first quarter of this year, with about 93 per cent of monthly income required to pay for a 40 square metre flat on an 80 per cent mortgage basis, down from the March 1991 high of 189 per cent. Hongkong Bank said the 70 per cent mortgage limit would remain ''a major constraint for home buyers''. Rising prices meant that the average deposit had grown to more than 70 per cent above its level in the third quarter of 1991, just before the cap was introduced following wild speculative excesses. The Government has said it has no early plans to lift the limit, but some buyers have avoided the limit by borrowing from developers. The bank said supply of residential flats would blow out this year and next year to 35,000 annually, the highest yet, and Government flats produced for sale would rise to 18,000 a year. Basing its estimates on projections, the bank said two thirds of the small-to medium-sized flats would be built in the New Territories, with Tuen Mun, Yuen Long and Sha Tin expected to be worst hit by oversupply. However, it said completions probably would not meet projections, moderating the expected ''greater downward pressure''. Price rises in the office sector would be limited by high vacancy and supply. ''Over 56 per cent of properties becoming available in the 1993-94 period will be located in the districts of Wan chai, North Point, Sheung Wan and Tsim Sha Tsui. In these areas, the large number of planned developments is likely to place pressure on prices and rents.'' Prospects were not much brighter for the commercial sector, where supply was expected to exceed demand in Wan Chai, Kwun Tong and the New Territories.