LONDON- A return of oil exports from Iran during Joe Biden's presidency is some way off according to trading company chiefs and OPEC sources, giving OPEC+ more time to adjust their supply pact.

The U.S. president-elect has said he'd return to Iran's 2015 nuclear deal if Tehran resumes compliance with the pact. President Donald Trump quit the pact in 2018, reimposing sanctions that cut Iran's oil exports sharply.

The prospect of a rise in Iranian supply has worried some in the Organization of the Petroleum Exporting Countries and its allies, a group known as OPEC+. 

But Gunvor Chief Executive Torbjorn Tornqvist said talks with Iran were unlikely in 2021.

"I don't think that [Iran negotiations] will necessarily occupy the president in his first year," Tornqvist told the Reuters Commodity Trading Summit. "He has other much higher priorities domestically."

Vitol Chief Executive Russell Hardy said at the ADIPEC conference the oil supply effect of the U.S. rejoining the nuclear deal was more likely to be an issue in the second half of 2021 rather than the first half.

And the chief executive of Mercuria Energy Trading also did not see more Iranian supply as imminent.

"Some people think there will be renewed discussions taking place in the next few months. If they do, one could imagine a slightly more flexible policy towards Iranian exports," Mercuria CEO Marco Dunand told the Reuters Commodity Trading Summit. "But I think this will take several months so this could be developing in the second part of next year."

Two OPEC+ sources do not expect sanctions to be eased swiftly.

"I think it will probably take six months or more," said a source familiar with Iranian thinking. "Therefore, OPEC+ has enough time."

Another source saw the issue as "manageable" because volumes wouldn't be back until end-2021.

(Editing by Kirsten Donovan) ((alex.lawler@thomsonreuters.com; +44 207 542 4087; Reuters Messaging: alex.lawler.reuters.com@reuters.net))