BEIJING (AFP) -- China's exports tumbled 6.6 percent year-on-year to 1.14 trillion yuan ($174 billion) in January, authorities said Monday, as the struggling manufacturing sector remained a drag on the world’s second-largest economy.

Tremors in overseas markets and weakness in partner economies have weighed on the Asian giant, a main driver of the world's economic growth, and the globe’s largest trader in goods.

Rock-bottom prices for commodities such as oil and the slowdown in infrastructure have hit China's import values, while exports have been hurt by frail overseas demand, along with rising labor costs and the increasing competitiveness of neighboring economies.

Imports fell sharply 14.4 percent year-on-year to 738 billion yuan in January, Customs said, a worsening of the 4 percent decline in yuan terms the month before. The monthly trade surplus rose 12.2 percent to 406 billion yuan, compared to a 24.7 percent expansion in December.

Economists had forecast exports to fall 1.8 percent in dollar terms last month, according to Bloomberg news, and expected a 3.6 percent slide in imports, also in dollar terms.

The benchmark Shanghai index opened 2.84 percent lower on Monday, as Chinese investors returned from the weeklong Lunar New Year holiday and responded to the rout in world markets last week.

The Chinese economy grew 6.9 percent in 2015 -- the lowest rate since 1990 -- and is expected to slow further this year.