AN increase in the number of upmarket Chinese restaurants, fast-food outlets and karaoke bars lifted the value of restaurant sector receipts to about $45.5 billion last year, up 18 per cent on 1991. After discounting the effect of price changes over the period, total receipts rose seven per cent in volume, according to provisional statistics released yesterday by the Census and Statistics Department. However, the Federation of Hongkong Restaurant Owners cautioned that the figure represented a mild growth after inflationary factors were taken into consideration. ''A lot of restaurants, with the exception of fast-food outlets and upmarket restaurants, are not doing so well as they have to struggle with high rents, wages and keen competition,'' said Mr William Mark, the federation's president. Mid-market restaurants were the hardest hit as they had to operate within narrow profit margins and low returns. At the same time, upmarket restaurants were benefiting from the increase in China-Hongkong trade, which spawned businessmen with ''fat'' entertainment accounts. ''Both Chinese and Hongkong businessmen involved in China trading don't care how much money they spend on entertaining and they like to dine in expensive upmarket Chinese restaurants, leading to the opening of more Shanghainese and Peking restaurants,''Mr Mark said. The total receipts of Chinese and non-Chinese restaurants both rose 16 per cent in value and five per cent in volume. The highest increase came from bar receipts which recorded a massive rise of 46 per cent in value and 29 per cent in volume. According to Mr Mark, there has been an increase in the number of karaoke bars and patronage of Western pubs by local Chinese which may have contributed to the high figure. ''Karaoke bars are the in-thing for the locals and they are very popular with the younger people. ''These bars are doing very well. Some of them are huge, with a capacity for 1,000 while the smaller bars can take in between 100 and 200 people. Many of them are in Tsim Sha Tsui and Causeway Bay. ''These bars enjoy good business throughout the week,'' he said. Mr Mark said there was also an upsurge in local patronage at Western-style pubs. However, a restaurant consultant expressed surprise at the figure as the increase in beverage spending had not been dramatic for the previous year. ''The figure suggests a dramatic surge in spending on beverage and to my knowledge, that is not happening in the industry,'' said Mr Richard Feldman. ''While there has been an increase in spending, it has not been to the figure of 46 per cent. ''Food is not a luxury item but beverage is and people have been becoming more conservative with their disposable income.'' Fast-food restaurant receipts recorded the second highest rise with a 29 per cent increase in value and 18 per cent in volume, a growth attributed to the rapid expansion of the market. According to the Hongkong Tourist Association, seven million tourists visited Hongkong and spent $47 billion, out of which 10.9 per cent was on meals outside hotels. ''Food is a major attraction for our visitors and we have outstanding Chinese cuisine,'' said Ms Penny Byrne, the association's assistant public relations manager.