TIANJIN - China's oversupply of petroleum products will worsen, as its oil refineries are running below 70 percent capacity, said an industry insider Sunday.

"Overcapacity has long plagued refineries, and the dipping of the global crude price has made overcapacity ever more prominent," said Cui Guanglei, deputy head of the refinery division of Sinopec Group, China's largest petroleum refinery.

On the consumption side, China is using more gasoline and less diesel, Cui said. Sinopec saw overall petroleum sales rise 3.1 percent in the first half of the year, with gasoline up 12.5 percent but with diesel falling.

Sinopec has been adjusting its production, trying to decrease the diesel-to-gasoline ratio of its products, but it is still under significant and increasing pressure from the consumption trend, Cui said.

As a comparison, refineries in the United States have been operating at around 90 percent capacity this year, according the US Energy Information Administration.