FACTBOX: Key facts about Kyrgyz parliamentary election

(Reuters) - Kyrgyzstan votes in a snap parliamentary election on Sunday in a ballot expected to hand a big majority to President Kurmanbek Bakiyev's Ak Zhol party.

Below are key facts about the December 16 election.

* A regular parliamentary election had not been due until 2010, but Bakiyev called a snap poll in October after a referendum that adopted a constitution boosting his powers.

* All 75 deputies will be -- for the first time -- elected through party-list proportional representation. Previously all elections were held on a single constituency basis.

* Parliament is elected for five years. Parties have to pass a five-percent overall barrier and separately win at least 0.5 percent of the votes in each of Kyrgyzstan's seven regions and two key cities.

* The previous parliamentary election in 2005 was deemed flawed by international observers and triggered violent protests that toppled Bakiyev's predecessor Askar Akayev. The Organisation for Security and Co-operation in Europe (OSCE) is sending more than 200 monitors to observe this week's vote.

* Twelve parties have been registered to take part in the election.

The following parties are seen as the main contenders:

AK ZHOL

Leader: Kurmanbek Bakiyev, president of Kyrgyzstan.

Created just before the election as "a party of the people and for the people", Ak Zhol includes a number of civil servants and former deputies.

President Bakiyev, 58, is not on the party list. Cholpon Bayekova, Chairman of the Constitutional Court, and Adakhan Madumarov, former Secretary of State, top the list.

Ak Zhol calls itself "a party of decisive actions and great responsibility." It promises to strengthen the democratic institutions and speed up economic development.

SOCIAL-DEMOCRATIC PARTY

Leader: Almazbek Atambayev, former prime minister (sacked by Bakiyev on November 28)

A moderate opposition party.

Atambayev, 51, spearheaded a wave of anti-Bakiyev protests in 2006. He later switched sides to help Bakiyev's government but remained loyal to the opposition movement.

Atambayev himself is not running in the election.

ATA MEKEN

Leader: Omurbek Tekebayev, former speaker of parliament.

Tekebayev, 49, became speaker after Akayev's fall in 2005, but quit last year after becoming a fierce critic of Bakiyev.

A more radical opposition party.

Describing itself as socialist, it unites a number of former members of parliament who helped drive Bakiyev to power 2005 but have since become disenchanted with the Kyrgyz leader.

AR-NAMYS

Leader: Felix Kulov, former prime minister

Kulov, 59, was behind 2005 protests that helped bring Bakiyev to power. He ended up allying himself with Bakiyev to become his first prime minister.

The two later fell out and Bakiyev sacked Kulov as prime minister in early 2007.

Ar-Namys (Dignity) has built its campaign around slogans denouncing corruption and nepotism. It has called for turning the country into a parliamentary republic and establishing closer ties with Russia.

THE REST OF THE FIELD

Eight smaller parties, including communists, are running for parliament.

(Writing by Olzhas Auyezov; Editing by Richard Balmforth)