They said sentiment was hit by fresh speculation that regulators will soon resume initial public offers (IPO) after earlier vague reports that the authorities planned to speed up the disposal of state-owned, non-tradable shares in listed companies.
The Shanghai A-share Index lost 17.83 points to 1,136.27 on turnover of 7.96 billion yuan (981.50 million dollars) while the Shenzhen A-share Index was down 6.39 points or 2.28 percent at 273.66 on turnover of 4.51 billion yuan.
The benchmark Shanghai Composite Index, which covers both A- and B-shares, shed 16.92 points or 1.54 percent at 1,080.87 on turnover of 8.02 billion yuan.
The Chinese yuan closed at 8.0840 to the dollar, up from its previous finish at 8.0862.
Dealers said rumours of a possible resumption of IPOs in the near future further increased liquidity concerns.
Oil refiners were under pressure from profit-taking on continuing concerns over their profitability - highlighted by Sinopec's third quarter results - given that the government continues to control their product prices to help keep inflation in check.