The Asian giant, still reeling from a big equity market sellof, has taken more steps to prevent further weakness.

China's securities regulator told brokerages yesterday review trades and enforce rules that require the use of real names and national identification numbers, becoming the latest step by policymakers to calm jittery markets after mainland equities slumped by a third from their 12 June peak.

Authorities have taken a number of steps - including bans on short sales – and have also blamed what they claim is illegal activity for some of the rout. The dramatic falls in prices, and the reaction of the government to the saga, has shaken confidence in the Chinese economy, although views differ on how damaging the episode will be.

Mainland China equities – “A-Shares” – had surged before mid-June, buoyed by the Shanghai-Hong Kong Stock Connect link, but the subsequent selloff has jolted global investors, and is arguably a more worrying development than Greece’s debt crisis.

The China Securities Regulatory Commission’s warning are designed to stamp out a ploy through which a single investor controls multiple accounts -- often registered under other people's identification numbers -- to bid the price of a stock up or down, the report said.

The news service quoted the official Xinhua news agency as stating that an investigation personally led by China's vice minister of public security Meng Qingfeng found certain brokerages were suspected of manipulating futures prices and other "malicious" trading.