The office said in its latest report that Iran's total crude exports to China rose 46.73 percent from January to July 2011 compared with the corresponding period of the previous year.

China imported about 16.2 million tons of crude oil from the Islamic Republic in the said time span, making Iran the third largest oil supplier of the Asian country after Saudi Arabia and Angola.

Iran is currently providing China with roughly 12 percent of its total annual oil demand.

The report added that Iran's crude oil exports to China hit 2.74 million tons in July, indicating a 35.07 percent rise against the same period of the previous year.

Late in July, the Iranian foreign ministry underscored that Tehran is selling crude to China without any problem, dismissing media reports that the country is facing problems in getting paid by its biggest crude customer.

"We have no problem in selling our oil to China," Foreign Ministry Spokesman Ramin Mehman-Parast told reporters in a weekly press conference here in Tehran.

"We see our oil cooperation with other countries in the framework of trade deals and economic cooperation," and our oil, banking and economic officials always do consultations to prevent any possible problem, Mehman-Parast added.