Extra time was needed to allow millions of latecomers to cast ballots in Iran's election on Friday, in what's been described as a crucial test for moderate President Hassan Rouhani's administration.

As well as picking 290 members of parliament, voters were also selecting the Assembly of Experts, a powerful committee of 88 clerics that monitors the work of the country's supreme leader Ayatollah Ali Khamenei. The group may also be roped in to choose his successor.

Across much of the country, polls closed at 10pm local time (18:30 UTC) but in the capital Tehran and other large cities, polling stations remained open until 11.45pm, state TV announced.

Electoral officials claimed that more than 28 million people had cast their ballot, which would mean a turnout of 51 percent, while long queues were seen outside polling stations in most major cities into the night.

The late finish means initial results from provinces and small cities will not come until Saturday and in Tehran, where some 5.5 million voters are electing 30 MPs, the outcome may take until Tuesday.

Winds of change

Rouhani has been credited with trying to improve ties with the West, which have been strained since Iran's Islamic revolution in 1979.

Having signed off on a nuclear deal with several world powers less than a year ago, his administration is hoping its "List of Hope" coalition will break conservative dominance in the legislature in order to push through domestic reforms.

"Whoever comes out [as the winner], either in parliament or the Assembly of Experts, with votes of the people, will be respected by us, and everyone will respect the votes of the majority of the people," Rohani said, after casting his vote.

However, no one expects the vote to usher in radical changes to Iran's domestic politics, which are controlled by the clergy and Iranian Supreme Leader Ayatollah Ali Khamenei, who has the final say on all state matters.

Khamenei's possible replacement

Khamenei underwent prostate surgery in 2014, and there has been renewed speculation about his health. But he appeared in an upbeat mood after voting in the capital and reiterated his suspicions over his country's nuclear deal with the West.

"Whoever likes Iran and its dignity, greatness and glory should vote. Iran has enemies. They are eyeing us greedily," Khamenei said.

Thousands of candidates excluded

The elections were preceded by just a week of campaigning, in which Rouhani had hoped to focus on how his administration had overseen a growing economy. His wishes were somewhat thwarted, however, as controversy erupted over which candidates were actually eligible to run for office.

Reformists claimed they were the worst hit by electoral bans as thousands of candidates were barred from participating.

Of a total 4,844 parliamentary candidates across the country, approximately 10 percent were women. Some 159 clerics sought positions on the 88-member Assembly of Experts.

mm/jr (AFP, AP, Reuters)