BEIJING (Reuters) - China's forex regulator said on Thursday it will crack down on fake overseas mergers and acquisitions used by some local firms and individuals to move assets out of the country, even as capital outflow pressure is easing.

The government will support "genuine" overseas mergers and acquisitions by Chinese firms, although rapid rises in outbound investment have had an impact on cross-border capital flows, Guo Song, an official with the State Administration of Foreign Exchange (SAFE), told a Beijing news conference.

"In the past year we found some Chinese firms and individuals moving assets overseas via outbound investment, this is certainly a key area of concern for us," Guo said, without disclosing details.

The authorities will "definitely put high pressure" on tackling fake overseas mergers and acquisitions, he said.

China will crack down on illegal activities to keep its foreign exchange markets stable, SAFE official Xu Weigang told the same conference.

The Chinese government has been encouraging local firms to invest overseas under Beijing's "One Belt, One Road" program, but rapid rises in outbound direct investment (ODI) have fanned concerns over increased pressure on China's foreign exchange reserves and external payments.

China's overall ODI jumped 18.3 percent in 2015 to a record $145.67 billion, surpassing the annual foreign direct investment that reached $135.6 billion, earlier government data showed.

Despite the phenomenon, pressure on cross-border capital outflows is easing, which will help lower depreciation pressure on the yuan <CNY=CFXS>, SAFE spokeswoman Wang Chunying said.

Du Peng, another SAFE official, however, said no "large-sized" capital outflow via fake trade deals has been detected by the supervisory body so far, and discrepancy between custom data and forex data is no proof that fake trade deals are happening.

Recent data showed net foreign exchange sales by China's commercial banks in August fell to the lowest in about a year, but net foreign exchange sales by the People's Bank of China in August hit the highest in six months, as the central bank sought to support the yuan.

Guo also said that the current quota on the Qualified Domestic Institutional Investor (QDII) scheme had been used up and the regulator is applying for an additional quota.

(Reporting by Kevin Yao, Qizi Sun and Yawen Chen; Editing by Richard Borsuk and Muralikumar Anantharaman)