China's trade surplus rose for the second month in August, up 14.9 percent to $28.69 billion from a year earlier.

The surplus last month was $28.69 billion, posting gains for the second month in a row. The figure was $25.28 billion in July and $24.97 billion last August.

Exports last month gained 21.1 percent to $134.87 billion, while imports climbed 23.1 percent to $106.18 billion, the General Administration of Customs said on Wednesday.

"Exports growth decelerated, but imports posted much bigger slow-down as commodities prices and shipping rates slumped," an official with the Ministry of Commerce told Xinhua on the condition of anonymity. "This is the main reason why the surplus jumped."

The slower advance in the Chinese currency against the US dollar also contributed to the surge.

"The yuan remained almost steady against the US dollar since July. This can help exports while giving no further incentives to imports."

The trade gap narrowed 6.2 percent annually to $151.99 billion in the first eight months of the year.

Exports increased 22.4 percent to $937.69 billion during the January-August period and imports were up 30 percent to $785.69 billion.