NEW DELHI: Asian refiners are set to buy more crude oil from Iran once they receive word on when sanctions will be lifted, expecting Tehran to price its oil competitively as it tries to rebuild market share in an oversupplied market.

World powers and Iran finally struck a deal on Tuesday after more than 20 months of talks, setting in motion the eventual lifting of sanctions on Iranian oil exports in exchange for curbs on the Islamic nation's nuclear programme.

Iran has said its priority destination for selling its crude is Asia, not surprising since China, India, Japan and South Korea are its largest customers. The four have sometimes been the country's only crude customers since toughened sanctions were put in place in early 2012.

Tuesday's nuclear deal sparked a flurry of checks among Asian governments and refiners to clarify when they will be allowed to import more oil from Tehran.

"If the nuclear deal permits, we will increase our purchases," an official from India's oil ministry said. "There are refiners like HMEL (HPCL-Mittal Energy Ltd) who want to buy Iranian oil."

B. K. Namdeo, who heads refineries at Hindustan Petroleum Corp Ltd, said: "We will look at buying Iranian oil if, after the deal, insurance is available for my refineries and Iran continues to offer discounts on crude sales and shipping."

For Iran to increase oil exports though, it needs relief from measures that block its access to global funds transfers and embargoes that prevent ships carrying Iranian oil and refineries processing it from being insured.

"An increase in Iranian oil exports can only occur once sanction relief occurs, tentatively in early 2016," Goldman Sachs analysts said in a note. Exports would also increase as floating storage of between 20 million and 40 million barrels is drawn down, the bank said.