LEGISLATIVE Councillors yesterday raised concerns that the proposed old-age pension scheme would push Hong Kong towards a large-scale social security system such as those in welfare states in the West. They feared that this would put further pressure on taxpayers and employers, who would, in the future, be asked to contribute more to the scheme. But Acting Secretary for Education and Manpower Lam Woon-kwong dismissed the concerns and said the scheme would provide only a basic guarantee of the welfare of the elderly. He said the scheme was different from the systems prevailing in Western countries. These provided various sorts of insurance on top of a monthly allowance. Mr Lam said the exact amount of contribution could be fixed only after conducting a consultancy study, but he promised that it would remain unchanged over the next 20 years. The Government's initial proposal, announced this month, suggested a three per cent salary contribution from both employers and employees. This would provide a pension of about $2,100 a month to people over 65. Mr Lam reiterated that it would mean substantive increases in profit and salary tax rates if the public did not contribute to support the elderly, because the elderly population would increase over the next 30 years. But legislators said the rate of contribution would probably increase after the scheme was implemented. Meeting Point legislator Dr Leong Che-hung questioned whether the Government was sure no extra money would be needed for services for the aged. ''Say for example, as the medical charges are getting higher and higher, are we going to spend some part of the money on medical insurance?'' Dr Leong said. ''I think the Government looks at the issue in a too simplistic way.'' Legislator and member of the Preliminary Working Committee (PWC), Ngai Shiu-kit, said the scheme did not address the problem of retirement protection for the elderly. He said it would impose a heavier burden on the working class while offering extra money to the rich. ''I find it unreasonable and ridiculous that the scheme asks those who cannot afford to pay to contribute while, at the same time, offering money to those who are rich enough to support themselves. ''It offers money to everyone without regard to their financial needs. This is a kind of welfare. It is fundamentally different from the principles of a retirement scheme,'' he said. Mr Ngai is co-ordinator of a PWC study group on retirement protection. The group will forward suggestions for a provident fund after 1997.