Chinese stocks opened much lower on Tuesday following Monday's collapse and the regulators' promise of support for the market.
The benchmark Shanghai Composite Index fell 4.09 percent to open at 3,573.14 points. The Shenzhen Component Index opened 4.06 percent lower at 11,986.25, Xinhua news agency reported.
The ChiNext Index, tracking China's NASDAQ-style board of growth enterprises, opened 5.11 percent lower at 2,546.41 points.
On Monday, the Shanghai index lost 8.48 percent to close at 3,725.56 points, the sharpest daily drop since February 27, 2007. Shenzhen fell 7.59 percent to close at 12,493.05 points.
China Securities Finance Corporation Ltd. (CSF) said Monday night it would continue to buy stocks to stabilise the market.
Zhang Xiaojun, spokesperson with the China Securities Regulatory Commission (CSRC), dispelled rumours that the national margin trading service provider has backed off from stabilising the stock market.
CSRC is investigating huge sell-offs by some individuals and will punish any malicious short selling, Zhang said.