LONDON - China's stock market is developing into a bubble and people run the risk of making irrational investments, a top Chinese legislator told the Financial Times.

"There is a bubble going on. Investors should be concerned about the risks," Cheng Siwei, vice-chairman of the standing committee of the National People's Congress, told the newspaper in an interview published on the FT's Web site late on Tuesday.

Cheng Siwei, vice-chairman of the standing committee of the National People's Congress, speaks at a forum in this file photo. China's main stock indices plummeted Wednesday as Cheng warned of a stock market bubble and irrational investments. [newsphoto/file]

"But in a bull market, people will invest relatively irrationally. Every investor thinks they can win. But many will end up losing. But that is their risk and their choice."

He added: "You can't take administrative measures to change people's behaviour. The market is based on people's behaviour. Investors will have to learn their own lessons."

Eight months into a rally that boosted the main Shanghai index 130 percent last year, the market's elated mood and lofty valuations would lead to fears of a crash elsewhere in the world.

But China's circumstances indicate a sharp drop is unlikely, and large sections of the market should keep rising this year, though at a much slower pace than in 2006, say most fund managers and analysts at local and foreign investment houses.