A woman holds a picture of Ebrahim Raisi as supporters celebrate his victory in Imam Hussein square in Tehran on Saturday. AFP

Ultraconservative cleric Ebrahim Raisi was declared the winner on Saturday of Iran's presidential election. Raisi won just shy of 62 per cent of the vote in Friday's election, according to official figures, on a turnout of 48.8 per cent, a record low for a presidential poll in the Islamic republic.

"I congratulate the people on their choice," said outgoing moderate President Hassan Rouhani, who has served the maximum of two consecutive four-year terms and leaves office in August.

Ebrahim Raisi waves after casting his ballot in Tehran. AFP

Raisi, 60, is set to take over at a critical time, as Iran seeks to salvage its tattered nuclear deal with major powers and free itself from punishing US sanctions that have driven a deep economic crisis.

"God willing, we will do our best so that the hope for the future now alive in people's hearts grows further," said Raisi, vowing to strengthen public trust in the government for a "bright and pleasant life together."

Raisi is seen as close to the 81-year-old supreme leader, Ayatollah Ali Khamenei, who holds ultimate political power in Iran. Friday's voting was extended by two hours past the original midnight deadline amid fears of a low turnout.

A woman casts her vote at a polling station in Tehran. AFP

Many voters chose to stay away after the field of some 600 hopefuls including 40 women had been winnowed down to seven candidates, all men, excluding an ex-president and a former parliament speaker. Three of the vetted candidates dropped out two days before Friday's vote.

'Save the people'

Populist former president Mahmoud Ahmadinejad, one of those barred from running by the Guardian Council of clerics and jurists, said he would not vote because "I do not want to have a part in this sin."

Ultraconservative Mohsen Rezai, a former commander of the Islamic Revolutionary Guard Corps, placed second with 11.8 per cent of votes cast.

Women voters pose with their stamped national identity booklets at a polling station in Tehran. AFP

He was followed by the only reformist left in the race, former central bank chief Abdolnasser Hemmati, who scored 8.4 per cent. Another ultraconservative, Amirhossein Ghazizadeh-Hashemi, came last with 3.5 per cent.

Khamenei hailed the election saying that "the great winner... is the Iranian nation because it has risen up once again in the face of the propaganda of the enemy's mercenary media."

On election day, pictures of often flag-waving voters dominated state TV coverage, but away from the polling stations some voiced anger at what they saw as a stage-managed election.

"Whether I vote or not, someone has already been elected," said Tehran shopkeeper Saeed Zareie. "They organise the elections for the media."

A woman arrives to vote at a polling station in Tehran. AFP

Enthusiasm was dampened further by spiralling inflation and job losses, and the Covid pandemic that has killed more than 80,000 Iranians by the official count.

Among those who queued to vote at schools, mosques and community centres, many hailed Raisi, who has promised to fight corruption, help the poor and build millions of flats for low-income families.

Women supporters of Ebrahim Raisi hold posters depicting him as they celebrate his victory in Tehran. AFP

A nurse named Sahebiyan said she backed him for his anti-graft credentials and on hopes he would "move the country forward" to "save the people from economic, cultural and social deprivation."

Raisi, who holds deeply conservative views on many social issues including the role of women in public life, has been named in Iranian media as a possible successor to Khamenei.

Agence France-Presse