SHANGHAI, Jan 19 (Reuters) - China shares fell on Tuesday as a resurgence of COVID-19 cases hit market sentiment, with consumer discretionary and materials stocks leading the retreat. ** The blue-chip CSI300 index fell 1.5% to 5,437.52, while the Shanghai Composite Index slipped 0.8% to 3,566.38. ** The tech-heavy start-up board ChiNext sank 2.1%, while the STAR50 index shed 2.5%. ** Leading the decline, the CSI300 consumer discretionary index dropped 2.9%, while the CSI300 materials index slid 2.7%. ** China is battling the worst outbreak of COVID-19 since March 2020, with one province posting a record daily rise in cases, as an independent panel reviewing the global pandemic said China could have acted more forcefully to curb the initial outbreak. ** China will provide necessary policy support for the economic recovery this year, to avoid a “policy cliff”, as small firms remain hard-pressed amid the pandemic, a senior official at the state planner said. ** China’s economy picked up speed in the fourth quarter, with growth beating expectations as it ended a rough coronavirus-stricken 2020 in remarkably good shape and remained poised to expand further this year even as the global pandemic rages unabated. ** Around the region, MSCI’s Asia ex-Japan stock index was weaker by 0.24%, while Japan’s Nikkei index closed up 1.39%. ** At 0716 GMT, the yuan was quoted at 6.4884 per U.S. dollar, 0.06% firmer than the previous close of 6.4921. ** As of 0717 GMT, China’s A-shares were trading at a premium of 34.71% over the Hong Kong-listed H-shares. (Reporting by Shanghai Newsroom; Editing by Subhranshu Sahu)