"As China's stock prices are soaring constantly, there has been a rise in the number of cases of illegal activities in the stock market, which has undermined the normal market order and threatened investor security," the ministry said in a notice on its official website.

The government has repeatedly warned investors of illegal securities companies that swindle clients of funds with claims of high returns.

The ministry said scam artists used Internet and phone calls to illegally tout stocks, funds or stock ownership to investors.

The swindlers charged unwary investors high fees for fake stock tips and then quickly disappeared after having collected a huge sum of money.

The funds or stock ownership, which were touted online or by phone, were often nonexistent, the ministry said.

Investors were also hoodwinked into buying fake "initial offerings" of stocks that were not listed on the exchanges.

Other scams include cases in which investors' shares were stolen and sold by criminals, who had stolen investors' account numbers and codes.

The ministry urged investors to be alert and not to trust promoters who touted unrealistic high returns, or accept stock tips from unidentified persons online or on the phone.

It also urged investors to be aware of computer security and to stop trading immediately when discovering a computer virus.

The China Securities Regulatory Commission has pledged to curb illegal trading and fraud in the stock market.

In February, the State Council approved the China Securities Regulatory Commission to lead a cross departmental team to crack down on illegal securities business.