Total direct investment offshore increased to just under $883 billion in 2014, Zhang Xiangchen, Deputy China International Trade Representative at the Ministry of Commerce (Mofcom), said.

The commerce ministry on Wednesday reported that non-financial outbound direct investment rose 18.2 percent to 473.4 billion yuan, or $77 billion, for the first eight months of the year.

Mofcom on Thursday also revised up its 2014 offshore non-financial direct investment tally to $107.2 billion from the $102.9 billion reported previously, taking total outward investment for the year to $123.12 billion.

"Our outbound investment has maintained a double-digit growth rate, and this trend will be sustained in future," Zhang told a media briefing.

China's slowing economy and market volatility is driving domestic firms to acquire foreign brands and technology, as well as diversifying, said Thilo Hanemann, Research Director at Rhodium Group in New York.

The Beijing government has rolled out policies to support the global efforts of Chinese companies, offering financial incentives and removing administrative controls on offshore deals.

Chinese firms have already announced or completed 390 deals worth $77 billion in the year to Sept 16, according to Thomson Reuters data, a doubling of the deal amount for the same period last year.

China's global M&A deal volume this year already surpasses the $70.4 billion in deals reached in 2008, formerly the biggest year so far for offshore mergers.

Industrial deals were the biggest transactions, led by China National Chemical Corp.'s buyout of Italian tire-maker Pirelli & C Spa for $8.88 billion, which included Pirelli's debt.

Many of this year's big-ticket deals were done by Chinese firms buying financial services businesses, including HNA Group Co.'s subsidiary Bohai Leasing Co., which paid $2.56 billion for aviation leasing firm Avolon Holdings Ltd.

By the end of 2014, 18,500 Chinese domestic investors had established nearly 30,000 enterprises overseas, with about 77 percent showing profits in 2014, Zhang said.

"State-owned firms and private companies are looking to buy overseas financial institutions that are yielding strong cash-flow and providing an international presence and market share," said Eugene Qian, China country head for UBS Ltd.