A court in Kyrgyzstan on Tuesday handed a firebrand opposition leader a hefty jail sentence on kidnapping charges, an official said, a ruling likely to prevent him competing in upcoming elections.

Sadyr Japarov, whose arrest in March provoked a violent protest outside the country's national security committee was found guilty of taking a former regional governor hostage during another rally in October 2013.

"The court sentenced the defendant to 11-and-a-half years imprisonment," the representative told AFP by telephone.

The court representative said Japarov, who has declared his intent to compete in presidential elections set for mid-October, was cleared of three other charges.

Some 59 candidates have filed documents to take part in the presidential race that will see incumbent leader Almazbek Atambayev's legally permitted time in office come to an end.

While ex-Soviet Kyrgyzstan is the most democratic country in a region dominated by long-ruling strongmen, it has also been the most politically volatile in recent times.

The Muslim-majority country experienced two revolutions that unseated presidents in 2005 and 2010 followed by ethnic violence that left over 400 dead.

Another jailed opponent of Atambayev's, lawmaker Omurbek Tekebayev, also risks exclusion from the race as he awaits trial on corruption charges.

Both Japarov and Tekebayev have claimed their trials were politically motivated.

Atambayev has said he has no plans to hold further political office after his term ends in December.

Japarov, who spent over three years living abroad prior to his arrest, is most famous for his vociferous opposition to the Kumtor gold mine that accounted for 8 percent of Kyrgyzstan's economy last year.

Opponents of the mine have consistently accused it of environmental abuses, allegations the mine's Canadian-headquartered operator Centerra says are groundless.

Several protests against the mine, including the October 2013 protest in which Issyk Kul governor Emil Kaptagayev was briefly taken hostage and doused in petrol, have turned violent.

Source: AFP