Iran's oil export has recently exceeded 2 million barrels per day (mbpd), the official said on condition of anonymity.
The volume of exports has returned back to the level before the EU ban, the official added, the Fars News Agency reported.
"Iran's measures to overcome the sanctions have been effective, so that the level of exports has been increased to the level before the sanctions."
Oil Minister Rostam Qasemi said in July that although the West seeks to topple the Islamic establishment by imposing sanctions against Iran's oil sector, the country's oil exports will never cease.
Qasemi emphasized that Iran's oil market will never close because oil consumer countries need Iranian crude.
"There are many ways to easily sell oil, one of which is to take advantage of businessmen and the private sector," Qasemi said.
In early 2012, the United States and European Union (EU) approved new sanctions against Iran's oil and financial sectors which aim to prevent other countries from purchasing Iranian oil or transacting with its central bank.
U.S. sanctions entered into force on June 28, while EU oil bans against Iran were enforced as of July 1.
Iran's oil crude export halved to 1.1 million barrels per day in July compared to 2011.