* SSEC +0.85%, CSI300 +0.9%

* Tech shares rebound from Tuesday's sharp falls

* Private survey shows faster service sector growth

SHANGHAI, Aug 4 (Reuters) - A bounce back in tech shares lifted up China's main stock indexes on Wednesday, as a private survey showed faster service sector growth, but worries over surging COVID-19 cases weighed on sentiment, keeping gains in check. ** At the close, the Shanghai Composite index was up 0.85% at 3,477.22. The blue-chip CSI300 index rose 0.90%. ** Tech shares rose across the board, with the CSI Info Tech sub-index gaining 2.42%. It fell 2.31% on Tuesday after a state media article described online games as "spiritual opium". ** Tech shares recovered even as an opinion article in the ruling Communist Party's official People's Daily newspaper said that China should better protect minors from the dangers of the internet. ** The smaller Shenzhen index ended up 1.7% and the start-up board ChiNext Composite index was higher by 2.47%. ** Providing some support for market sentiment, a private survey showed that growth in China's services sector accelerated in July, helped by a recovery in consumption. ** But a surge in domestic COVID-19 cases remains a threat to the growth outlook. China reported the most number of new locally transmitted cases since January on Wednesday. ** The CSI300 financial sector sub-index fell 0.64%, the consumer staples sector lost 1.72%, the real estate index slid 0.95% and the healthcare sub-index slipped 0.58%. ** Around the region, MSCI's Asia ex-Japan stock index was firmer by 0.81%, while Japan's Nikkei index closed down 0.21%. ** At 07:13 GMT, the yuan was quoted at 6.4611 per U.S. dollar, 0.14% firmer than the previous close of 6.47. ** So far this year, the Shanghai stock index is up 0.1% and the CSI300 has fallen 4.5%, while China's H-share index listed in Hong Kong is down 12.6%. Shanghai stocks have risen 2.35% this month. (Reporting by Andrew Galbraith; Editing by Rashmi Aich)