The amount of vacant government land could be enough to support the city's housing supply for four years, the latest official figures suggest. The Development Bureau released the figures to the Legislative Council yesterday after the Secretary for Development, Paul Chan Mo-po, was accused last month of being vague when explaining how much land was available for housing and of holding back stocks. He said there were about 2,000 hectares of vacant government land, but about half was reserved for small houses. He made the comment to back the government's plan to develop three new towns in the New Territories to increase housing supply. But a bureau spokesman said yesterday: "We want to tell people that it is not true that there is plenty of land lying idle and that the government is holding it back. The actual situation is that a lot of these sites are not necessarily developable. The new towns project is necessary to build up our land bank for the long term." He said that of the 2,154 hectares of vacant public land zoned for residential use, only 391.5 hectares was suitable for housing, while a further 932.9 hectares was suitable for "village-type development", that is, small houses. The remaining areas were not suitable as they involved roads, man-made slopes or temporary public works. The spokesman said the identified areas were still being studied before confirming they were suitable for housing, but refused to estimate how many homes they could yield. Assuming plot ratios of one to five for sites of five density classes, the South China Morning Post calculated the 391.5 hectares could yield 178,900 flats of 600 square feet each. This could support the government's annual supply target - 40,000 public and private homes - for more than four years. The bureau would not say how many small houses the 932.9 hectares of unused village sites could deliver. Officials were also evasive about how much of the land reserved for village housing could be converted to other housing. The bureau said some land was in the middle of existing villages and therefore could not be used to build flats, while other sites were at village fringes and also might not be suitable for other use. Analysts estimate the land can support villagers' demand for four decades to even a century. Lawrence Poon Wing-cheung, of the Institute of Surveyors, estimated that village land could yield 50,210 small houses of 700 square feet each, while Edward Yiu Chung-yim, a former real estate professor at the University of Hong Kong, put this at 133,900. Poon based his estimate on each house needing a site of 2,000 square feet to accommodate gardens and roads, while Yiu estimated that each house would need just a 750-square-foot site. As for how many years of demand their estimates represented - based on the annual average of 1,315 small-house applications received in the past decade - Poon's estimate works out to 38 years, while Yiu's came to 103 years. Lawmaker Gary Fan Kwok-wai, who had asked for the land figures, said the government should give full disclosure of village land, including how many sites could be used for other types of housing.