Iranians voted on Friday in a parliamentary election which is expected to reinforce the power of the clerical establishment of Supreme Leader Ayatollah Ali Khamenei over hardline political rivals led by President Mahmoud Ahmadinejad.

The election is unlikely to have much impact on Iran's foreign policies - the country's disputed a high turnout to bolster their legitimacy. Nuclear programme and international relations are already strictly controlled by Khamenei.

But it could allow the clergy to strengthen its hand in determining the political backdrop ahead of a presidential election due in 2013.

With Iran facing growing international isolation, western sanctions over its nuclear programme and a threat of attack by Israel, Iranian leaders have been calling for

There is a lot of negative propaganda against our nation ... The arrogant powers are bullying us to maintain their prestige. A high turnout will be better for our nation ... and for preserving security, said Khamenei after casting his vote.

Whenever there has been more enmity towards Iran, the importance of the elections has been greater.

The election will be the first since the country's disputed presidential election in 2009, when opposition and pro-democracy protests were quelled by security forces.

This time round, leading reformist groups have said they will stay away from voting, setting the stage for a straight contest between backers of Khamenei and Ahmadinejad.

A low turnout, however, could nonetheless highlight the extent to which disappointment still exists among Iranian voters over the outcome of the 2009 presidential election.

State radio reported polling stations opened to voters at 8 a.m. (0430 GMT). They are due to close at 6 p.m. (1430 GMT), although this time has been extended in past votes.

While voting stations in affluent northern Tehran were quiet, people queued in central and downtown parts of the city to cast their votes.

I am here to support my establishment against the enemies' plot by voting, said Mahboubeh Esmaili, 28, holding her baby outside the Hoseiniyeh Ershad polling centre in central Tehran, where around 50 people were queuing up to vote.

ECONOMY AN ISSUE

The two main groups that are competing for the 290-seat parliament are the United Front of Principlists, which includes Khamenei loyalists, and the Resistance Front that backs Ahmadinejad.

Ahmadinejad, the son of a blacksmith, still enjoys the support of many in Iran's poorer communities, largely thanks to his humble image and regular cash handouts. But his popularity has been dented by the country's economic crisis.

Western sanctions aimed at forcing Iran to halt sensitive nuclear work have started to hurt energy and food imports. The West fears Iran is working on developing a nuclear bomb, but Tehran says the programme is for electricity generation and other peaceful purposes.

The price of staple goods has spiralled because of the falling value of the Iranian currency and fresh European Union and U.S. sanctions on Iran's financial and oil sectors.

Critics have accused Ahmadinejad of making things worse for ordinary Iranians, saying his decision to replace food and fuel subsidies with direct monthly payments since 2010 has fuelled inflation, officially running at around 21 percent.

Khamenei will be looking to use the vote to re-establish his hold on power following a political rift between the two leaders when Ahmadinejad tried to supersede Khamenei in Iran's complex political hierarchy.

Analysts have said Ahmadinejad and his allies have been trying to undermine the central role of the clergy in politics by emphasising nationalist themes of Iranian history and culture in their speeches.

While Ahmadinejad himself cannot stand for a third term under

Iran's constitution, some Iranian media reports said he backed Esfandiar Rahim-Mashaie, his chief 0f staff, as a candidate to succeed him in the 2013 presidential vote.

The Supreme Leader's campaign got a boost when powerful establishment groups - including influential clerics, the elite Revolutionary Guards and powerful bazaar merchants - formed an alliance to back his loyalists.

The Guardian Council, made up of six clerics and six jurists who vet candidates, has approved 3,467 individuals out of more than 5,382 who initially applied to run in the poll.

Some politicians said that the hardline council barred many established Ahmadinejad supporters, forcing him to pick younger political unknowns.

Khamenei, who initially endorsed Ahmadinejad's 2009 re-election, publicly distanced himself from the president in April by reinstating the sacked intelligence minister.

In the past months, dozens of Ahmadinejad allies have been detained or dismissed from their posts for being linked to a deviant current that his rivals say aims to sideline clerics. Ahmadinejad's media adviser has been sentenced to one year in jail for insulting Khamenei.

Reformists did not send in list of candidates, saying the basic needs of a free and fair vote had not been fulfilled.

Major pro-reform political parties have been banned and leading reformists have either been jailed or banned from political activities since the 2009 election, which the opposition says was rigged.

Opposition leaders Mirhossein Mousavi and Mehdi Karoubi, defeated in the 2009 vote, have been under house arrest for more than a year.

(Writing by Parisa Hafezi; Editing by Myra MacDonald)