China plans to triple the limit for purchases of local shares by foreign institutional investors, the government said Monday, just ahead of key trade talks with the United States.

The State Administration of Foreign Exchange said in a notice on its Web site that the quota for such share purchases by qualified foreign institutional investors (QFII) would rise to $30 billion from the current $10 billion.

It did not give an exact date for when the long-anticipated change would take effect.

Yuan-denominated shares are off-limits for most foreign investors. China originally limited QFII purchases to $4 billion when it launched the program in 2002.

China committed to raising the limit in earlier economic talks with the US, the Xinhua News Agency cited Shang Fulin, chairman of the China Securities Regulatory Commission, as saying.

"China has underscored its intention to open up the country's financial markets," Xinhua said in describing the decision to triple the quota for qualified foreign investors.

The State Administration of Foreign Exchange, which oversees foreign exchange policies and dealings, said it would also expand channels for Chinese to invest overseas.