SHANGHAI, Jan 28 (Reuters) - China stocks fell sharply on Thursday as persistent tight cash conditions in the interbank money market stoked fears that policymakers may be starting to shift to a tighter stance to cool gains in share prices and property markets.
** Hong Kong shares also declined, tracking overnight sell-offs on Wall Street.
** One of China's key short-term money rates surged to a near six-year high, driven by a combination of the central bank's extended net drain of cash from the financial system and higher holiday demand.
** The People's Bank of China (PBOC) injected 100 billion yuan ($15.44 billion) via open market operations earlier in the day, but it still withdrew 150 billion yuan on a net basis as 250 billion yuan was set to expire. It has drained a net 568.5 billion yuan so far this week.
** At the midday break, the Shanghai Composite index was down 1.48% to 3,520.28. The blue-chip CSI300 index was 2.36% lower at 5,397.61, poised for its biggest one-day decline in percentage terms since July 24, 2020.
** The financial sector sub-index eased 1.68%, the consumer staples sector fell 1.34%, the real estate index lost 1.99% and the healthcare sub-index dropped 2.09%.
** The smaller Shenzhen index was down 2.09%, the start-up board ChiNext Composite index was weaker by 2.72% and Shanghai's tech-focused STAR50 index was down 1.15%.
** "Alongside the previous PBOC warning on asset bubbles, fears of deleveraging drove China and Hong Kong equities lower," said Ken Cheung, chief Asian FX strategist at Mizuho Bank in Hong Kong, adding such market fears could discourage capital flows into Chinese stock markets.
** Chinese H-shares listed in Hong Kong fell 1.85% to 11,435.48, while the Hang Seng Index was down 1.97% to 28,721.27.
** Traders said losses in Hong Kong shares came as investor sentiment soured after the safe-haven dollar rallied following a sell-off on Wall Street and delays in coronavirus vaccine rollouts shook optimism about an early recovery for the global economy.
($1 = 6.4779 Chinese yuan)