China is facing a major coal oversupply in three major ports, the state-run Xinhua News reported.

As of end June, coal inventories in Qinhuangdao, Tangshan and Huanghua, have reached 18.3 million tonnes, or 8.6 million tonnes, 8.4 million tonnes and 1.3 million tonnes, respectively. Of the three major coal ports, Qinhuangdao Port in north Hebei province is the world's largest coal loading port.

The oversupply in inventory was due to the country's slowed domestic economic growth, which prompted in turn reduced demand for thermal coal in China.

"China's coal stocks are estimated at about 300 million tonnes, equivalent to the entire country's coal consumption in one month," Li Xin, a senior official with the China Coal Transportation and Distribution Association, said in Xinhua News.

China's 86.55 million tonnes coal imports in the first four months of the year, a 70 per cent jump from a year ago, further exacerbated the situation.

"The increase of imported coal affected the price of domestic coal, as well as the domestic coal market," Song Xinting, vice president of the Coal Transportation and Distribution Association of Hebei province, said in Xinhua News.

Statistics from the National Energy Administration earlier showed China's power consumption in May hit 1.96 trillion kilowatt hours, a 5.8 per cent hike from a year ago, but it was 6.2 percentage points down from the same period in 2011.

The coal pile at Qinhuangdao started in May, Xinhua News reported. On June 18, it reached 9.46 million tonnes, its highest since November 2008. The port's capacity volume for pile is at 10.18 million tonnes.