Sinopec Group, Asia's largest oil refiner, said its huge Puguang gas field in southwest China's Sichuan province had not been affected by a strong earthquake that struck the region on Saturday.

Spokesman Lv Dapeng said a pipeline that supplies gas from the field, one of China's largest, to the city of Shanghai was also functioning normally, as were its service stations in the region.

The company had prepared reserves of fuel to help with relief efforts, Lv said.

Sichuan is one of the four major natural-gas-producing provinces in China, and its output accounts for about 14% of the nation's total.

China's top oil company, PetroChina, which also has oil and gas production facilities in the province, could not immediately be reached for comment.

The firm has said that it plans to start a trial run of its 200,000 barrels-per-day Pengzhou refinery in Sichuan this month.

Construction of the plant, the largest refining and chemical complex in southwestern China, was briefly halted in 2008 after an earthquake that killed some 70,000.

On Saturday, a 6.6 magnitude earthquake hit the province killing at least 28 people and injuring at least 100.