It marked a 23.8 percent increase from a net purchase of $6.3 billion in September.

In the first 10 months, Chinese banks made net foreign exchange purchases of $37.7 billion, SAFE, the forex regulator, said in a statement on its website, www.safe.gov.cn

Despite the net purchase in the spot foreign exchange market in October, SAFE said Chinese banks were net sellers of $600 million in the forwards market, which may ease some market concerns about a surge in capital inflow pressures.

SAFE earlier on Wednesday played down the risk of hot-money inflows into China, saying that forex supply and demand is basically balanced in the onshore market with expectations on the yuan's exchange rate stable.

China has the world's largest foreign exchange reserves, standing at $3.29 trillion at the end of Q3, accumulated as a function of the country's capital controls which saw exporters and investors sell dollars to Chinese banks, which in turn sold most of them to the central bank in the interbank market.

But commercial banks have sold less foreign currency to the central bank, the People's Bank of China (PBOC), in recent months in response to easing restrictions on FX holdings and borrowings.

The PBOC's share of foreign exchange purchases fell to 2 percent of the total in September, or just 2 billion yuan ($320 million). In September 2011, the PBOC's share was 97 percent of the total, or 239.4 billion yuan.

The central bank had earlier said China's entire banking system bought a net 21.6 billion yuan in foreign exchange in October, down sharply from a net purchase of 130.7 billion yuan in September.

The central bank will release its foreign exchange purchase data for October later this month.