Voting in the elections to the Central Asian former Soviet republic's single-chamber 75-seat parliament, the Jogorku Kenesh, began at 0800 GMT on Sunday.
The election is being closely watched as it is seen as a stepping stone to presidential polls on 30 October at which incumbent leader Askar Akayev has vowed to stand down - a potential first for the Central Asian former Soviet republics as none of their leaders has stepped down at polls since the Soviet Union's 1991 collapse.
Akayev has warned against letting the "virus" of Western-backed unrest take hold, referring to recent popular uprisings that ousted members of the post-Soviet old guard in Georgia and Ukraine.
But there have already been several demonstrations in support of candidates disqualified from standing amid claims that the
authorities want to closely control the result.
In the rural Tonsk region the election has been delayed by two weeks until 13 March due to disruption by voters angered at a member of the outgoing parliament's disqualification from the race.
Some 2.6 million people are eligible to vote in this mainly impoverished mountain republic, which has a total population of around five million.
For the first time voting is to be entirely constituency based,
in line with controversial constitutional changes in 2003.
Previous polls have been criticised by the West as flawed.