The exact boundary of a marine park in the northern New Territories where luxury apartments are planned for sale to overseas buyers is being disputed. The dispute is over whether part of the proposed development site on the southern coast of the Hoi Ha Marine Park falls within the marine reserve, as it lies below the high tide line that marks the park boundary. If this argument is substantiated, it means any development on that particular portion of the site would be subject to stringent restrictions such as specific approval by the Country and Marine Park Board. The site is planned for 'seaside luxury residences' with up to 50 houses, which the Tokyo-based JHC Capital Group had been promoting on its website although the firm has never obtained approval from the government for the development. A survey carried out earlier by the Civic Party found the high tide mark - which determines the shoreline or boundary of the marine park - was about 40 metres further inland than indicated by a government map of the park. The party demanded the administration adjust the park boundary to match the shoreline to prevent further undesirable development in the area, home to two-thirds of locally found coral species. 'We have sent a letter to the Country and Marine Park Board to clarify the situation of the land, but so far it has not answered,' said Paul Zimmerman, a Civic Party member and chief executive of Designing Hong Kong. The Agriculture, Fisheries and Conservation Department last night said it would not change the park boundary. A spokeswoman would not confirm if the department was aware of the shifting shoreline but did not rule out possible movement being the result of erosion or weathering. The boundary was set in 1996 when the park was designated by the government. Meanwhile, the Country and Marine Park Board yesterday backed in principle a proposal to designate up to 40 hectares of slopes above Tai Au Mun Road as a country park. The area is one of seven studied by the agricultural department for expansion of Clear Water Bay Country Park, which will lose five hectares to a landfill extension in Tseung Kwan O. The department had said it would not compensate for the loss of the land because there was no such mechanism under the law, but promised to look for new sites to expand the park.