TEHRAN: Iran's President Hassan Rouhani inaugurated five new phases of the South Pars gas field on Sunday, the result of some $20 billion in investment, local media reported.
The ribbon-cutting of phases 17-21 pave the way for Iran to surpass the production levels of neighbouring Qatar, which shares half the offshore gas field, Iranian officials said.
"Our production has reached 575 million cubic metres per day," said Rouhani.
Iran's total gas production is 885 million cubic metres per day.
"At the height of sanctions, with the help of Iranian engineers and workers, we succeeded in developing 11 phases of South Pars," added Oil Minister Bijan Namadar Zanganeh.
South Pars is the largest known gas reservoir in the world.
Iran has the second-largest gas reserves in the world after Russia, and the fourth-largest oil reserves.
In November, French firm Total signed a preliminary accord worth an estimated $4.8 billion (4.5 billion euros) to help develop phase 11 of South Pars, but has since said it will wait for signals from Washington before finalising the deal.
Although many sanctions, including on Iran's energy industry, were lifted under a nuclear deal with world powers in 2015, the US has maintained a raft of its own sanctions that continue to hamper investment and cause concern among foreign businesses.
Since the nuclear deal came into effect in January 2016, Iran has increased oil production from 2.6 million barrels per day (bpd) to 3.9 million, while more than doubling its oil exports.
In January, Tehran approved 29 international companies to bid for oil and gas projects.
However, it is still finalising a new contract for foreign investors -- a process that has proved controversial in a country with strong memories of past exploitation by global oil firms.