MOTORISTS will be spared higher registration and licensing fees in the near future, despite the need for short-term solutions to stem the growing number of cars in the territory, senior officials said yesterday. People would instead be ''encouraged'' to use more public transportation, it was said. The Transport Department would consider ''further means of constraining'' the growth of private car use if these efforts failed, said Secretary for Transport, Mr Michael Leung Man-kin. Mr Leung admitted that the existing policy of high registration and licence fees had failed to contain car numbers. Industry watchers said the first registration tax of 120 per cent of a car's value was ineffective because motorists treated it as an acceptable part of the cost of owning a car. Mr Leung said the number of private car registrations rose 10 per cent last year to about 237,000. He said the department would look to other countries' examples for solutions, but ruled out importing Singapore's system of road taxes. ''The road is a limited system and cannot be used over its capacity,'' he said. ''It is a question of managing the peak hours and giving priority to vehicles such as buses because they are mass carriers. They carry more people and are more efficient,'' heexplained. Chairman of the policy working group for the Transport Advisory Committee, Professor Tenny Lam Chung-yu, said motorists would always see a need to drive whatever the cost. The executive director of the Automobile Association of Hongkong, Mr Phil Taylor, blamed traffic-flow problems on the number of traffic bottlenecks and claimed they could be solved but for the Government's unwillingness to spend money on proper road maintenance and building. Mr Leung, however, said the road network was undergoing a major overhaul with 20 projects committed and another 12 major projects recommended in an updated Comprehensive Transport Study. A total of $3.8 billion would be spent on these in 1992-93 and another $6.5 billion in 1993-94.