Oil Minister Gholam Hossein Nozari said the oil field held 1.1 billion barrels of sweet crude oil, of which 233 million was recoverable, the oil ministry's Shana news agency reported.
He told reporters after a cabinet meeting that the field is in the area of Andimeshk town in Khuzestan province of southwestern Iran that borders Iraq. No further details were immediately available.
Iran is the number two producer in OPEC and the number four worldwide, although its ability to reach oil production targets has been hampered by a lack of international investment.
Production started in February from Iran's biggest onshore oil field, Azadegan, which is estimated to have 42 billion barrels of crude oil in place.
