China's imports from Africa fell nearly 40 percent last year, officials said Wednesday, as low commodity prices and slowing growth in the Asian giant hit trade.

Imports from the continent fell to 440 billion yuan, some 38 percent lower than in 2014, China's Customs administration said.

Natural resources from Africa such as iron ore and oil have helped fuel China's economic boom, and it became the continent's largest trade partner in 2009, giving it growing diplomatic influence.

But growth in the world's second-largest economy has slowed to its lowest since the aftermath of the global financial crisis, punishing world prices for commodities -- the bedrock of African exports.

Economists say Chinese growth is becoming less dependent on heavy industry, further hitting demand for raw materials.

However, Chinese exports to Africa rose by about 4 percent to reach 670 billion yuan, officials said.

Oil exporters are expected to be hit especially hard. China said its imports from Nigeria slumped more than 50 percent by value last year.

Beijing said in November its direct investment in Africa dropped "more than 40 percent" to about $1.2 billion in the first six months of the year.

China's President Xi Jinping announced $60 billion of assistance and loans for Africa last month, signalling ongoing commitment to the continent despite the investment drop.