THE manufacturing industry still holds promise because it is becoming less labour-intensive and more technological, says Herbert Liang, president of the Chinese Manufacturers' Association. After officiating at the opening of Plastics Asia '94 and Pack Print Asia trade covention yesterday, Mr Liang said manufacturing remained the base of Hong Kong's industry, although many believed that it had been overtaken by the services sector. ''The manufacturing industry's margin in gross national product shows a decrease because of the service sector's fast growth,'' he said. ''However, the actual manufacturing industry figure's numbers show an increase.'' Although several manufacturing companies had moved to China, Mr Liang saw new promise in Hong Kong with a shift in production focus. China was not as much of a threat as technically advanced centres in Europe, he said. Hong Kong was an important centre for manufacturing, as certain types of sophisticated plastics goods and machinery were produced primarily in the territory, he said. Plastics exports from Hong Kong - the fifth largest export item - increased 21-fold over the past 30 years. However, it is generally held that China is becoming the top manufacturing centre in Asia. B & I Group of Companies general manager Alan K. H. Kwok echoed this view: ''It's a fact China is the fastest-growing centre.'' B & I has had business dealings in China for the past 10 years. It holds up to 20 industrial trade fairs in China a year. Mr Liang, who was also optimistic about the manufacturing industry in China, said the mainland's Most Favoured Nation trading status would be renewed ''without a doubt''. He said many US Congressmen wanted to separate human rights from trade issues, referring to the 105 officials who wrote to President Bill Clinton proposing such a move.