China's central bank on Friday said it was raising lenders' required reserves by 50 basis points, effective Dec 20, its sixth official increase this year.

The move, following an interest rate rise in October and two reserve requirement increases in November, is Beijing's latest step to mop up excess cash in the economy.

The government announced a shift to a prudent monetary policy from the previous moderately loose stance in early December, which analysts said could presage more aggressive tightening.

(Reporting by Zhou Xin and Simon Rabinovitch; Editing by Don Durfee)