Crude prices hit a record near $120 a barrel last month, although they have since slipped back a few dollars. Iran and other OPEC states have repeatedly blamed factors like the weak U.S. dollar and speculation, not supply issues, for the rise.
"The fluctuations have an upward tendency now and the possibility of seeing very high oil prices by the end of the year is not unlikely," Hojjatollah Ghanimifard, international affairs director of the National Iranian Oil Company, said.
"High prices are not because of a supply shortage by anyone," he told reporters in Tehran.
He referred to "oversupply" going into storage and also said the annual overhaul of refineries was dampening consumption.
Consumer nations such as the United States and Britain have urged the Organisation of the Petroleum Exporting Countries to pump more crude to help cool prices. But OPEC has rebuffed those calls. Iran is the No. 2 OPEC oil producer.
