According to PIN, the new oil layer forms part of the Band-e-Karkheh oil field northwest of Ahvaz, capital of Iran's oil-rich southwestern province of Khuzestan, said Gholam-Hossein Nozari on Saturday, on the sidelines of the International Oil, Gas and Petrochemistry Exhibition in Tehran.

Nozari said that the oil field's estimated reserves increased to 4.5 billion barrels with the discovery of the new layer.

A gas field with an estimated reserve of 6 trillion cubic feet was also discovered in the central province of Fars, he added.

The report comes on the back of recent announcements from Tehran of the discovery of eight new oil fields in April alone. No details have yet been given on the exact amounts of their reserves.

Iran, OPEC's second biggest oil producer, controls about 5 percent of global oil supply and sits on the world's second-largest gas reserves.

Iran has formed a partnership with India's state-run oil firm ONGC to produce liquefied natural gas (LNG) in the Farzad gas field in Farsi block, which is estimated to hold recoverable gas reserves of 12.8 trillion cubic feet.

Iran has not yet exported any LNG but says it will be able to produce 77 million tons a year by 2014.