Iran's oil exports are at their normal levels and are unaffected by Western embargoes, an Iranian oil official was quoted as saying on Sunday.
"We don't see anything abnormal, almost everything is progressing routinely," Mohammad Ali Khatibi Tabatabaei, director for international affairs at the National Iranian Oil Company (NIOC), told the Iranian Students' News Agency (ISNA).
He did not give any figures on Iran's current oil export levels, Reuters reported.
Iran's top oil customers have slashed Iranian purchases under pressure from European Union and U.S. sanctions that aim to squeeze Tehran's oil income and curb its nuclear programme.
Japan's imports of Iranian crude fell to zero in July for the first time since 1981, trade ministry data showed last week. To compensate, Japan increased imports from the United Arab Emirates and Iraq, among other suppliers.
South Africa imported no crude oil from Iran in July, customs data showed last week. The country used to import a quarter of its crude from Iran.
The EU's embargo also included a ban on insurance of Iranian cargoes. Tehran has offered to provide up to $1 billion of insurance cover to Iranian vessels shipping oil.
"This step has been taken in the last few months and everyone saw that the insurance companies could provide $1 billion in coverage," Tabatabaei was quoted as saying.