OPEC will welcome Iran’s full return to the oil market when sanctions are lifted, the secretary general of the Organization of the Petroleum Exporting Countries (OPEC) said Monday.

Iran is an OPEC member, although its oil exports are subject to US sanctions aimed at curbing Tehran's nuclear programme.

Secretary General Haitham Al Ghais, who is visiting Tehran for the first time, also told Iranian oil ministry's website SHANA that Iran has the capacity to bring on significant production volumes within a short period of time.

"We believe that Iran is a responsible player amongst its family members, the countries in the OPEC group. I’m sure there will be good work together, in synchronization, to ensure that the market will remain balanced as OPEC has continued to do over the past many years," SHANA's English-language website cited him as saying.

Although US sanctions can penalize any third party engaged in Iranian oil exports, Tehran ships daily close to one million barrels of crude to China, often disguised as cargos from third countries. Before the US imposed its sanctions in 2018 and 2019, Iran was exporting around 2.2 million barrels per day and in if sanctions are lifted Iran’s export capacity can hardly surpass that without major investments in the sector.

Saudi Arabia, the kingpin of OPEC, and Iran announced in March that they would restore diplomatic relations after years of hostility, in a deal brokered by China, the world's No. 2 oil consumer.