Iran's oil reserves stand at 158 billion barrels, a report said on Sunday.
Last October Iran upped its reserves figure to 150.31 billion barrels from a previous estimate of 138 billion barrels.
The report by the Iranian students news agency quoted Oil Minister Rostam Qassemi as saying his plan to concentrate on extracting crude from fields shared with other countries would boost production.
"By the end of the Fifth Development Plan (2010-2015), the country's oil production must increase to 5.2 million barrels per day (bpd) and this should happen from the country's joint fields," it quoted Qassemi as saying.
Hormoz Qalavand, head of the state-run National Iranian Southern Oil Company told FNA on Wednesday that Iran's current output stands at 3.92 million bpd.
Iran, which sits on the world's second largest reserves of both oil and gas, is facing US sanctions over its civilian nuclear program.
Iranian officials have dismissed US sanctions as inefficient, saying that they are finding Asian partners instead. A large number of Chinese, Indian and other Asian firms have negotiated or signed up to oil and gas deals with Iran.
Following US pressures on companies to stop business with Tehran, many western companies decided to do a balancing act. They tried to maintain their presence in Iran, which is rich in oil and gas, but not getting into big deals that could endanger their interests in the US.
Yet, after oil giants in the West witnessed that their absence in big deals has provided Chinese, Indian and Russian companies with excellent opportunities to sign up to an increasing number of energy projects and earn billions of dollars, they started showing increasing interest to invest or expand work in Iran.
Some European states have also voiced interest in investment in Iran's energy sector after a gas deal was signed between Iran and Switzerland three years ago regardless of the US sanctions.