Iran counting votes after election.

Sky News - Parliamentary elections have ended in Iran after almost 16 hours, with counting starting in the Interior Ministry in Tehran and governor's offices in the provinces.

The elections pitted conservatives loyal to the religious establishment against supporters of President Mahmoud Ahmadinejad.

More than 3400 candidates are competing for 290 seats in the legislature, with some 48.2 million eligible voters in the country of 74 million people.

Conservatives blame Ahmadinejad for poor economic policies and for using nationalistic slogans to distance his faction from the Islamist system.

The polls opened at 8am (1530 AEDT Friday) and were supposed to be closed at 6pm (0130 AEDT Saturday), but the Interior Ministry said that the massive turnout of voters at polling stations required a six-hour extension until midnight (0730 AEDT).

According to state media, turnout was huge.

The Interior Ministry, which has not given a date for the release of final results, said the process of counting votes has been partially automated.

Results from the provinces are expected to gradually come in on Saturday, with vote counts from the big cities, including the Tehran district, in the coming days.

The main outcome of the elections will be clarified after the results of the big cities, especially the 30 seats in the capital Tehran, are reported.

The rural areas do not have the political significance of the big cities, and results there do not show any clear trend.

A reformist wing in the race is seen to have little support.

The hard core of reformists, accused by the establishment of having turned into dissidents, have boycotted the polls, citing lack of freedom for all political parties.

The main divide is over Ahmadinejad, who faced punishing measures after daring to challenge the near-total authority of Supreme Leader Ayatollah Ali Khamenei last year.

Some ultraconservative blocs in the parliament races seek to show fealty to Khamenei and further slap Ahmadinejad, who is in his second four-year term, the maximum under Iran's term limits.

Ahmadinejad's allies hope to give him a political rebound and a chance - although diminishing - of having a protege as his successor.

The Ahmadinejad foes appeared to have the upper hand in the final weeks of the campaign.

The Iranian reformist opposition through its websites urged voters to boycott the election.

The Kalame website of reformist leader Mir Hossein Moussavi said that Iranians should stay home out of solidarity with opposition leaders who are under house arrest - such as Moussavi and fellow reformist Mehdi Karroubi.

The outcome of the election is unlikely to change the basic policies of the Islamic republic or alter Tehran's uncompromising stance in its dispute with foreign powers who suspect Iran of attempting to build a nuclear weapon.

The election is a first test for Ahmadinejad since his re-election in 2009, in a poll overshadowed by allegations of fraud, which sparked street protests.

Ahmadinejad and his deputy, Mohammad-Reza Rahimi, cast their votes in a mosque in southern Tehran but refrained from giving statements.

Ali Larijani, the top candidate for the conservatives and a fierce critic of Ahmadinejad, said he had no enmity toward his political rivals.

'Elections are for competition and not enmities, and whoever wins the polls should try to help developing the country,' Larijani said after casting his ballot.

His remarks were seen as an effort by the parliamentary speaker to play down his differences with Ahmadinejad over political and economic issues.

'Those who win the polls should serve the people and those who lose accept defeat,' Larijani said.

In Tehran, Khamenei made no direct reference to Iran's nuclear program, but clearly had the showdowns in mind as he appealed for a high voter turnout.

'Because of the controversies over Iran and increased verbal threats ... the more people come to the polling stations, the better for the country,' Khamenei said after casting his ballot.

'The higher the turnout, the better for the future, prestige and security of our country,' he added.

'The vote always carries a message for our friends and our enemies.'

Iranian state TV went live from several polling stations in Tehran and the provinces, showing long lines of people waiting to vote, followed by a commentary saying it was 'disappointment to the bad-wishers'.

Groups of foreign journalists were allowed in to cover the election, with some TV crews taken by bus to visit polling stations.

State TV claimed the US and its allies were hoping for a low turnout that would show divisions and a weakened Islamic theocracy, making it easier for outside forces to pressure Iran over the nuclear issue.

State TV also showed Hasan Khomeini, grandson of the late founder of the Islamic Republic in 1979, casting his vote.

He has close ties with reformers.

In 2008 and 2004, turnout for parliamentary elections were 57 per cent and 51 per cent, respectively.

The Fars news agency predicted turnout this year of more than 65 per cent.

Ahmadinejad has made few public comments about the elections - perhaps because of his lightning rod status in Iran's internal political feuds.

His sister, Parvin Ahmadinejad, is running for a seat in Garmsar, about 60 kilometres southeast of Tehran.

She is currently a member of Tehran municipal council.

The splits over Ahmadinejad began last year after he dared to challenge Khamenei over the choice of intelligence chief and other policies.

The ruling clerics answered back by arresting or purging dozens of Ahmadinejad's political allies.