By Sylvia Westall

KUWAIT (Reuters) - Kuwaitis voted on Saturday in a parliamentary election overshadowed by an opposition boycott, protests over a change to the polling rules and a festering political crisis in the U.S.-allied oil producer.

The election is the second this year in the Gulf Arab state, where a series of assemblies have collapsed under the weight of a power struggle between MPs and the cabinet, appointed by the prime minister who is chosen by the ruling emir.

Tens of thousands of Kuwaitis marched on Friday, urging people not to vote in protest at a change to electoral rules they say will skew the outcome in favor of pro-government candidates.

Emir Sheikh Sabah al-Ahmad al-Sabah used emergency powers in October to cut the number of votes per citizen to one from four, saying his decree would fix a flawed system and maintain security and stability.

The opposition, which is made up of Islamist, tribal and liberal lawmakers, as well as youth groups, says the new voting rules are an attempt to skew the parliamentary election in favor of pro-government candidates.

"There is a need for the decree to take the country out of the crisis are in," 51-year-old government worker Khaled Nouri said after voting in an upmarket district south of the capital.

"The wheel of development must continue to turn."

Opposition figures have refused to stand because of the voting rules change ordered by the emir, whose family has ruled for 250 years and dominates the cabinet.

LIMITS

Under the new rules, each voter chooses only one candidate instead of four, a move the opposition says will prevent its candidates winning the majority they had in the last vote.

In the past, candidates have called on supporters to cast their additional ballots for allies. They say such informal affiliations are crucial due to a ban on political parties.

"The old system was unfair for people in some areas of Kuwait," 28-year-old Dalal al-Aboud said at a voting station in a suburb on the edge of Kuwait City.

"I think it will be better if we try this new method, then we judge if it is fair or not."

The OPEC member state has the most open political system in the Gulf and tolerates more dissent. Parliament has legislative powers and the ability to question ministers.

Polls opened at 8 a.m. (0500 GMT), and about 423,000 Kuwaitis are eligible to cast ballots to choose the 50 members of parliament. Voters trickled into stations set up in about 100 schools around the country.

Officials in polling stations in several districts said turnout did appear lighter than usual, but final figures would only be ready later in the day. Polls close at 8 p.m. (1700 GMT) and results may come around three hours later, officials said.

TURNOUT CRUCIAL

University professor Alia Shuaib said women, who received the right to vote in 2005, were still finding it an uplifting experience to cast their ballots.

"I believe it is my duty as a woman and as a Kuwaiti national to vote," she said.

"It is a pleasure to get up, dress, get my papers and vote. It is breathtaking," the 45-year-old said. "I believe every person should vote and put the right people in parliament. We want educated people, the best."

Past turnouts in elections have been around 60-80 percent, but analysts said the numbers could be lower this time, given the boycott and exhaustion after the long string of elections.

"Voter apathy is to be expected, after all this is not only the second parliamentary election of 2012, but elections were also held in 1992, 1996, 1999, 2003, 2006, 2008, and 2009," IHS Global Insight analyst Jamie Ingram wrote in a note.

Information Minister Sheikh Mohammad al-Mubarak al-Sabah said there was a "significant and positive" voter turnout in the second district which comprises the capital and nearby areas.

The opposition tends to dominate voting in districts furthest away from the capital.

Near a polling station in the south of the country, where tribal candidates have polled strongly in the past, Ahmed al-Azemi said he would not vote because his tribe was boycotting the election.

"The Azemi family, we are against the election," he said. "The new parliament will last only a month. A National Assembly without the opposition is useless."

Around him men sat drinking tea and arguing about the boycott. Asked who had voted, three of the 10 raised their hands, to shouts from the others.

"I think people want to pick a better parliament," said Mohammed al-Harbi.

The opposition won around two-thirds of the National Assembly in February and formed a bloc that put pressure on the government, forcing two ministers from office.

That parliament was dissolved after a June court ruling, the latest stage in a standoff which has stalled investment and economic reforms.

"We would love to change the MPs. The previous parliament disrupted projects and then accused the government of delays," 50-year-old dealer Fahad Hamad said after casting his vote in a Kuwait City suburb. "There was no benefit at all."

(Additional reporting by Ahmed Hagagy and Mahmoud Harby; Editing by Sami Aboudi and Sophie Hares)