A CONTROVERSIAL planned golf course in Sai Kung ran into more problems yesterday when legislators questioned the $500 million cost. About 50,000 junior golfers were expected to use the course over the next five years, said Secretary for Recreation and Culture James So Yiu-cho, and a modestly priced public course was necessary. However, legislators were concerned about the aims of the Royal Hong Kong Jockey Club-financed and managed club on Kau Sai Chau - an island east of Sai Kung town. Supervision after completion was also a concern. United Democrat the Reverend Fung Chi-wood asked why the $500 million had not been used to develop other recreational areas which would benefit more people. He thought the centre might not recover its full cost. ''It's very expensive to manage a golfing centre. I wonder whether 'self-financing' is an empty slogan.'' ''Also, what does a 'moderate rate' of charges mean? There could be a crisis without a credible body to monitor the club's operation and to control charges.'' Meeting Point's Dr Leong Che-hung said 50,000 golfers would not be enough to finance such an expensive project. He said the promise of an economically run golf centre which might ask only a 10th of private clubs' green fees, was insufficient to ensure public access. ''Say a ferry link between Sai Kung town and the golfing centre is vital, who is going to monitor the fares? We have to consider these questions carefully.'' Mr So rejected financial concerns, saying Ocean Park, also financed by the Jockey Club, was earning huge profits despite a difficult start. He said the golf centre would be handed over to a statutory, non-profit making body as soon as revenues were earned. Profits would be retained for further improvements and development of other golfing centres. The official confirmed that the centre, with two 18-hole courses, would run on a first-come, first-served basis. ''It would be fully open to the public, except when local or regional championships are held.'' The 158-hectare golf course, with a capacity of 640 golfers a day, is expected to be completed late next year. The scheme has been criticised for potential damage to mangrove swamps and historic sites on the island. Legislators were told that a proposed dam had been relocated upstream to minimise the mangrove loss. One hectare of mangroves affected would be transplanted to other sites. A three-stage study, co-ordinated by the Antiquities and Monuments Office, to investigate and record archaeological finds was also completed. Jockey Club construction projects controller John Halliday said use of chemicals, such as fertilisers and herbicides, would be minimised by employing new techniques in grass-planting.