Iran's President Hassan Rouhani will address the nation on state television later on Monday after nuclear talks with world powers were extended for seven months.

"He will talk to the people," Iranian news agencies said, shortly after diplomats in Vienna announced that Monday's deadline for a final nuclear deal had been missed, setting a new date of June 30 next year.

Live appearances for the president are rare, but on October 13 he used a late night television interview to say Iran and the West would solve the nuclear crisis, even if there was no agreement by November 24.

Iran and the P5+1 group of nations (Britain, China, France, Russia, the United States plus Germany) implemented an interim deal in January that gave Tehran some relief from economic sanctions in return for curbs on its disputed nuclear program.

But the road to a final deal has stalled since because of disputes on the extent of uranium enrichment Iran would be allowed to undertake and on the timetable for sanctions on the Islamic republic to be lifted.

The missing of Monday's deadline followed a failure to agree a full deal by July 20, the original target date.

Rouhani, elected last year, has staked a lot of credibility on finding a solution to the nuclear issue.

His aim has been welcomed abroad but he has also come under pressure back home from hardliners who say Iran has already made too many concessions to the P5+1 group.

Iran insists its nuclear program is entirely peaceful but the West has not yet accepted its assurances and believes Tehran's activities could mask the long-term military plan of building an atomic bomb.