China stocks extended their rally on Wednesday, as investors awaited more powerful market rescue measures after Beijing signalled that authorities were ramping up efforts to support sagging markets.

Hong Kong shares seesawed but finished the morning session slightly lower.

** The blue-chip CSI 300 Index rose 0.5%, while the Shanghai Composite Index grew 0.9%.

** Hong Kong's Hang Seng Index edged down 0.1%, and the Hang Seng China Enterprises Index lost 0.7%.

** Chinese authorities have announced a raft of measures to aid stock markets in the past few days after Chinese stocks plunged to five-year lows last week.

** Some of the latest measures include curbs on short selling, and state fund Central Huijin Investment's expanded stock buying.

** Small cap index CSI 500 and CSI 1000 rebounded 6% and 5%, respectively, on Wednesday following the widened stock-buying support by the state fund, dubbed the "national team".

** "The recent market turmoil may prompt more decisive and quick moves by the national team to help restore confidence and prevent a self-fulfilling cycle," HSBC economists said in a note.

** Most sectors were up in the mainland market with the healthcare sector leading the gains.

** Wuxi AppTec's Shanghai-listed shares jumped 7.4%, its Hong Kong shares also up 6.7%, after a U.S. draft bill targeting Chinese biotech giants showed an update that the number of co-sponsors dropped to 0 from 6. Shenzhen-listed BGI Genomics also jumped 7.8%.

** Hong Kong-listed Chinese tech firms retreated 0.8% after a 7% rally on Tuesday. (Reporting by Summer Zhen; Editing by Janane Venkatraman )