"Negotiations are under way with international companies for investment in this project," Gholam-Reza Manouchehri, deputy head of National Iranian Oil Company for engineering and development, said at the Iran Oil and Gas Show.

"Currently, the designing of the Iran-Oman gas pipeline is going ahead smoothly and outline agreements have been reached with the Oman government," he said.

Iran signed an agreement with Oman in 2013 to deliver 28 million cubic meters of gas per day to the Persian Gulf littoral state for 15 years. The two nations hope the gas flow will begin by 2020.