Mohammad-Reza Mehdi-Pour, managing director of Iran's East Oil and Gas Production Co., said gas fields along the eastern border produced as expected, the Oil Ministry's official news agency Shana reported.
He added gas production from the Khangiran and Gonbadli fields has outpaced regional refinery capacity by more than 10 percent.
Iran is the third-largest natural gas producer in the world. Much of its production comes from the South Pars gas field in the Persian Gulf.
Iran's semiofficial Mehr News Agency reported Tuesday five of the 12 wells from phase 12 operations should begin in mid-April.
Iranian Deputy Oil Minister Mansour Moazami said, however, China National Petroleum Corp. was at risk of losing its $4.7 billion contract for South Pars development.
He told the Wall Street Journal, in an interview published Monday, there were "many, many" development delays from CNPC.
"We are giving a first warning, a second warning," he said. "Maybe in the end, we will terminate the contract."