SHANGHAI stocks fell the most in one week after data showed worse-than-expected manufacturing activity in May.

The benchmark Shanghai Composite Index slumped 1.16 percent to 2,275.67 points, the lowest since May 16. Turnover was 111.1 billion yuan (US$18.1 billion).

The HSBC Flash China Manufacturing Purchasing Managers' Index, a preliminary reading of the country's factory activity, declined to 49.6 in May, the lowest in seven months, due to weak demand at both home and abroad.

A reading below 50 indicates contraction.

The Shanghai market retreat also took cue from a 7.3 percent plunge of Japan's Nikkei 225 Average, which hurt the investor sentiment.

Cement producers led the decliners. Anhui Conch Cement Company, China's largest cement producer, dropped 3.2 percent to 17.31 yuan. Shaanxi Qinling Cement Group similarly shed 3.6 percent to 5.84 yuan.