CHINA'S relaxation of import controls on some electronic products will lead to greater sales of Hongkong goods in China, says the Hongkong Electronics Association. ''This is good news. It means an expanded market for Hongkong's electronics industry,'' said executive director Charles Chapman. ''The United States and Europe - our largest markets - have weakened in the last two years. Many manufacturers are now making efforts to enter the China market,'' he added. This week, China's Ministry of Foreign Economic Relations and Trade removed import licence requirements and quotas for instant cameras and import quotas for instant film. Controls on importing oscilloscopes and digital programmed telephone switching systems were also eased. These came within months of China's announcement of a cut in tariffs on 3,371 items including electronic products. ''Import licensing involved a lot of documentation and red tape. Some goods would need documentation from up to 10 departments where corruption might take place,'' said Mr Chapman. Import duties were higher than 100 per cent of the price for some items. ''All these made it difficult to sell legally to China, resulting in smuggling activities,'' said Mr Chapman. The easing of controls would reduce the chances for corruption and the greater number of imports could also clamp down on smuggling, he added. ''This makes fairer ground for competition. Hongkong manufacturers will now have more room for development across the border,'' said Mr Chapman. Although the country buys only about three per cent of Hongkong-made electronic goods, mainland sales last year rose 20 per cent on those of 1991, according to association chairman Robert Li Shu-keung.