SHANGHAI, April 15 (Reuters) - China stocks had a good start to the week with major indexes up as investors interpreted the new guidelines on the country's capital market as a positive signal for the stock market. Hong Kong shares declined.

China's securities regulator issued draft rules on Friday to strengthen the supervision of company listings, delistings and computer-driven programme trading, in a move to improve the stock market and protect investors' interests.

UBS strategist Lei Meng believes that the updated policies would fundamentally guide the long-term healthy development of the capital market, improve the quality of listed companies and boost market confidence. ** At the midday break, the Shanghai Composite index was up 1.21% at 3,055.99 points. ** China's blue-chip CSI300 index was up 1.9%, with its financial sector sub-index 1.68% higher, the consumer staples sector rose 2.36%, the real estate index advanced 1.01% and the healthcare sub-index jumped 1.43%. ** Chinese H-shares listed in Hong Kong fell 0.41% to 5,855.59, while the Hang Seng Index was down 0.73% at 16,599.34. ** The smaller Shenzhen index was up 0.26%, the start-up board ChiNext Composite index was 2.1% higher and Shanghai's tech-focused STAR50 index was up 1.91%. ** Around the region, MSCI's Asia ex-Japan stock index was 0.85% weaker, while Japan's Nikkei index was down 1.04%. ** The yuan was quoted at 7.2386 per U.S. dollar, 0.02% weaker than the previous close of 7.2372. ** The largest percentage gainers in the main Shanghai Composite index were Shaanxi Construction Machinery Co Ltd, up 10.13%, followed by Wolong Resources Group Co Ltd, gaining 10.07% and Shanghai Shyndec Pharmaceutical Co Ltd , up by 10.05%.

** The three biggest H-shares percentage decliners were SenseTime Group Inc, falling 4.55%, Li Ning Co Ltd , lost 4% and Xpeng Inc was down 3.74%. (Reporting by Shanghai Newsroom; Editing by Sonia Cheema)