China's yuan funds outstanding for foreign exchange grew each month during the first half of this year, official data showed Thursday.

The funds stood at 21.52 trillion yuan (about 3.2 trillion U.S. dollars) at the end of June, up 7.61 billion yuan from a month earlier, according to the People's Bank of China (PBOC).

June's increase followed a rise of 9.1 billion yuan recorded in May.

As the Chinese currency is not freely convertible under the capital account, the central bank has to purchase foreign currency generated by China's trade surplus and foreign investment in the country, adding funds to the money market.

Such funds are an important indicator of cross-border foreign capital flows and domestic yuan liquidity. An increase in the funds usually signals eased capital flight pressure, while a decrease often means higher capital flight pressure.

China's foreign exchange reserves remained relatively stable at 3.1121 trillion U.S. dollars at the end of June, up 0.05 percent from May, earlier data showed.

"China has ample foreign exchange reserves and relatively large room for policy controls. China is capable and confident in coping with all sorts of challenges," said Wang Chunying, spokesperson for the State Administration of Foreign Exchange, at a press conference Thursday.