CHINA overtook the US as the world's top oil importer last December, as shale gas filled in for American energy needs.

The US imported 5.99m barrels of oil on the average day in December last year, according to the Energy Information Administration (EIA) crashing down from November's 6.70m average, and imports as high as 7.88m just a few months before in August.

But at the same time China's net imports continued to grow, as its economy's pace of expansion continues only slightly dimmed, rising to 6.12m barrels a day, according to the Chinese customs authorities.

This comes as US crude oil production soared in the same month to its highest level in 21 years – 7.03m barrels produced per day – on the back of investment into revolutionary fracking technology, which allows engineers to get at oil trapped in sedimentary rocks called shale. As recently as last December the US was producing only 6.04m barrels per day, the EIA said.

The Chinese customs data, first reported by the Financial Times, comes after China overtook the United States as the world's top trader in goods.