SHANGHAI, June 12 -- China has vowed more stringent oversight of its listed companies to protect investors and curb speculation in the stock market, the stock regulator said Sunday.

Authorities will enhance regulatory supervision of public companies listed on China's domestic A-share market by improving information disclosure and corporate governance, said Jiang Yang, vice chairman of China Securities Regulatory Commission (CSRC) at Lujiazui Forum in Shanghai, which runs Sunday through Monday.

Regulators will strengthen supervision of activities related to listed firms' major shareholders and asset restructuring, and urge listed firms to deliver returns to investors through organic growth, Jiang said.

He added that the authorities will roll out tougher regulations and enhance monitoring of market activities to identify problems at an early stage, though he did not elaborate.

Global index compiler MSCI will announce this month whether it will include China's A-shares into its widely tracked stock indices.

Poor corporate governance is among concerns global investors have raised as obstacles to A-shares inclusion into the MSCI benchmarks.

Last month, the Shanghai and Shenzhen bourses set time limits on trading suspension for listed firms over mergers and acquisitions, and private placements, the latest move to strengthen oversight of listed firms and foster a more value-driven investment sentiment in China's stock market.