Existing rules of origin for Hong Kong products are likely to apply to more than half of the 273 classes of goods whose export to the mainland will enjoy zero tariffs from January under Cepa, says Financial Secretary Henry Tang Yin-yen. But an additional requirement - that processes in Hong Kong add at least 30 per cent to an item's value - would be imposed in some cases, he said. Mr Tang told a Trade Development Council seminar that a definition of what a good of Hong Kong origin was would be ready this month. Under the Closer Economic Partnership Arrangement signed in June, 273 categories of goods imported to the mainland from Hong Kong will be exempt from tariffs. The categories cover 90 per cent, by value, of the city's exports to the mainland. All other goods of Hong Kong origin will be tariff-free by January 2006. At present, most goods must have undergone principal manufacturing processes in the city to be labelled 'Made in Hong Kong'. For example, textile and clothing products must have undergone manufacturing processes such as spinning, weaving and cutting in Hong Kong to meet the criteria. Eden Woon Yi-teng, chief executive of the Hong Kong General Chamber of Commerce, said the 30 per cent value-added requirement would still be less onerous than provisions in other free-trade pacts, which require more than 50 per cent of the value of a good to have been added in its declared place of origin. Most Hong Kong manufacturers have moved their factories over the border, and Paul Yin Tek-shing, vice-president of the Chinese Manufacturers' Association of Hong Kong, said: 'We hope processes such as research and development will be classified as principal processes in determining the definition of Hong Kong goods.'