SHANGHAI, May 17 (Reuters) - China stocks rose on Tuesday, as Shanghai achieved the long-awaited milestone of three straight days with no new COVID-19 cases outside quarantine zones, while Hong Kong-listed tech firms jumped on hopes of crackdown on the sector being relaxed.

The CSI300 index rose 0.9% to 3,991.34 at the end of the morning session, while the Shanghai Composite Index gained 0.3% to 3,082.66.

The Hang Seng index added 2.2% to 20,395.66. The Hong Kong China Enterprises Index gained 2.6% to 7,000.38.

** The milestone Shanghai achieved usually means "zero COVID" status and could lead to the beginning of the lifting of restrictions. A nationwide COVID-19 caseload also declined, with 1,100 new cases reported on Monday, down from 1,227 new cases on Sunday.

** "The good news is the headline COVID case number has been falling," Nomura said in a note, but "we are not at a turning point yet."

** "The outlook for economic fundamentals and most financial assets in coming months will be largely determined by Beijing's stance on its zero-COVID strategy rather than the number of daily cases."

** China's state planner will strengthen support for manufacturers, the service sector and small firms, it said on Tuesday, as China's retail and factory activity fell sharply in April due to wide lockdowns.

** Semiconductors, new energy firms and automobiles surged between 2.2% and 5%.

** The Chinese People's Political Consultative Conference (CPPCC), China's top political consultative bodystarted a meeting to discuss how to promote the development of the digital economy, state media reported.

** J.P. Morgan analysts upgraded some Chinese internet companies on Monday and expect "significant uncertainties" faced by the sector to abate following recent favourable regulatory announcements.

** Hong Kong-listed tech giants rose more than 4%, with index heavyweight Alibaba Group surging 5.4%, while Tencent and Meituan gained more than 3% each.

(Reporting by Shanghai Newsroom; Editing by Rashmi Aich)