By Loucoumane Coulibaly and Ange Aboa
ABIDJAN (Reuters) - Ivory Coast held its first parliamentary election for a decade on Sunday, a relatively peaceful vote which was expected to strengthen President Alassane Ouattara's ruling coalition and make it easier for him to rebuild a nation crippled by war.
The election was boycotted by the party of former president Laurent Gbagbo, who is now in The Hague facing war crimes charges, over allegations of unfair treatment of Gbagbo supporters.
Election officials and observers said voting had gone peacefully despite some incidents, although turnout was lower than the over 70 percent recorded during the presidential election last year that sparked clashes between Gbagbo and Ouattara supporters.
"Overall, the election took place peacefully in polling stations visited in the district of Abidjan and the interior (of the country)," the United Nations Secretary-General's Special Representative for Ivory Coast, Bert Koenders, said in a statement.
More than 5 million voters had the chance to cast their ballots for a parliament for the first time in a decade in a vote seen as a crucial step toward recovery after a decade of conflict and political turmoil.
"In most polling stations in our school, participation rate was at between 35 and 40 percent, no higher," said Siriki Traore, head of a polling station in Yopougon, a pro-Gbagbo stronghold in the commercial capital Abidjan.
Turnout during the country's last parliamentary election in 2000 was at about 33 percent.
Ouattara, whose supporters invaded the capital and captured Gbagbo after he refused to accept Ouattara's victory in the presidential poll, urged Ivorians to vote saying parliament had an essential role in rebuilding the country.
"Ivory Coast is at work and we need to build the institutions that will now be strong and independent institutions. I am applying myself to this task and that's why the December 11 vote is an essential vote for all Ivorians," Ouattara said after casting his ballot in Abidjan.
"We are going to continue the electoral process in March or April 2012 with municipal and regional election," he said.
Ouattara's ruling coalition, which includes his RDR party and the allied PDCI, appears set for a landslide win based on voting patterns during the first-round of last year's presidential polls.
The poll could boost investor confidence in world's top producer of cocoa, which is also looking at expanding its gold mining, oil, cotton and services sectors so as to take back its place as the west African region's economic powerhouse.
Election officials said results of the poll would start trickling in later on Sunday evening and most of the results would be known by Tuesday.
Ivory Coast state radio said the election was peaceful across the country with no major incidents reported.
In Bonon however, a locality in the centre of the country near Daloa which produces about a quarter of Ivory Coast's cocoa, local authorities said a vehicle ferrying ballot boxes, voter rolls and ballots, was hijacked by armed men.
Pockets of lingering tension and violence in parts of the country, particularly in the west, had raised concerns of trouble during the polls, which were secured by local and about 7,000 United Nations forces.
Ivory Coast defence minister said the government had taken measures to ensure security during the vote with police, gendarmes and army deployed across the country.
"We have deployed about 25,000 troops on the ground to deal with any eventuality. We have closed the border in the west of the country to avoid any incidents and strengthen our security apparatus as well," Paul Koffi Koffi told journalists, adding that no incidents had been reported so far.
In Gagnoa, Gbagbo's birthplace in the west, tension remains palpable over his transfer to The Hague.
"There are SMS messages circulating in the area asking people not to vote," said Joel Zadi who lives on the outskirts of Gagnoa. "People did not like Gbagbo's transfer."
Nearly 1,000 candidates are vying for the National Assembly's 255 seats, according to the electoral commission.
(Writing by Bate Felix; editing by Philippa Fletcher)