Kyrgyzstan begins voting on Sunday to elect a new president who will determine whether bold reforms to create Central Asia's first parliamentary democracy will succeed in the divided and restive former Soviet republic.

A clean election in Kyrgyzstan would signal the first peaceful handover of the presidency in the mainly Muslim country after 20 years of failed authoritarian rule, the culmination of reforms set in motion after a bloody revolt toppled the president last year.

"We want an honest president who can uphold the law, somebody who will not allow the country to be divided by clans or by north and south," said 43-year-old Bishkek schoolteacher Aida, who declined to give her second name.

Two challengers to the front-runner, the Moscow-backed Prime Minister Almazbek Atambayev, have said they will contest the results if they believe violations have taken place, raising the spectre of protests by disgruntled supporters.

Instability in Kyrgyzstan worries the United States and Russia, which operate military air bases in the country of 5.5 million people and share concerns over drug trafficking and the possible spill over of Islamist militancy from Afghanistan.

Those who took power after an April 2010 revolution, led by outgoing President Roza Otunbayeva, have watered down the powers of the president and established parliament as the main decision-making body in Kyrgyzstan.

Atambayev, the pro-business prime minister, is the flag-bearer of these reforms. His policies are closest to those of Otunbayeva, who will step down at the end of 2011.

"A parliamentary system is more suited to the nomadic spirit of the people," Atambayev told reporters after casting his vote. "After 20 years, we are convinced that we don't need absolute power, which can transform itself into dictatorship."

Opinion polls have made Atambayev, 55, the clear favourite.

"He's a grafter," said retired construction worker Nikolai Dubovik, 77, who braved the first snow of winter to vote early at a school in the capital Bishkek.

But analysts question whether he can secure the outright majority required at the first attempt. If he falls short, he will face a strong challenger from the south in a run-off.

"With God's help, I will secure a second round," said Adakhan Madumarov, a three-times national billiards champion and former deputy prime minister whom many believe presents the greatest challenge to Atambayev.

Kyrgyzstan's economy, which relies heavily on remittances from migrant workers and the production of a single gold mine, has returned to growth this year after contracting in 2010.

But per capita GDP, at below $1,000, is less than a tenth of that in Kazakhstan, its oil-rich neighbour to the north. The country ranked level with the Democratic Republic of Congo in Transparency International's 2010 Corruption Perceptions Index.

"The current authorities have done a lot, but not everything they promised," said 53-year-old architect Kubanbaike Aliaskarov. "The price of gasoline is hitting us in the pocket. Sugar has nearly doubled in price."

The election also threatens to expose a north-south cultural divide. Atambayev, from the more Russian-leaning and industrial north, faces challenges from Madumarov and a second candidate who can draw on the nationalism of voters in the poorer south.

Madumarov, 46, wants to reverse the constitutional reforms to give equal prominence to the presidency and parliament.

The other leading southern candidate, trained boxer and former emergencies minister Kamchibek Tashiyev, has said "millions" would take to the streets to overthrow the country's leaders if they believed the elections to be unfair.

In the village of Gulbakhor, home to 3,000 ethnic Kyrgyz in the snow-capped mountains around the main southern city of Osh, residents voted overwhelmingly for Madumarov, who has vowed to spend half his time outside the office if elected president.

"He's young and honest, and his pockets are empty. He does not pursue selfish goals," said pensioner Kamchy Aliyev, 82.

But ethnic Uzbeks in the south were voting for Atambayev. Many believe his close ties with Russian Prime Minister Vladimir Putin will protect them from a repeat of the June 2010 ethnic violence in which nearly 500 people were killed.

"Here in Kyrgyzstan, he is called 'Another Putin'. Uzbeks would have a breather, and a new lease of life, under him," said Bakhriniso Rakhmanova, 58, who lives close to Osh.

The next president will be allowed by the current constitution to serve a single 6-year term and will appoint the defence minister and national security head.

The field of 16 candidates and the unpredictability of the result mark Kyrgyzstan out in formerly Soviet Central Asia, a region otherwise governed by authoritarian presidents.

"In the context of the region, Kyrgyzstan is different," said Walburga Habsburg Douglas, head of the Organisation for Security and Cooperation in Europe's observation mission.

"The people have a genuine choice of candidates, who are presenting different programmes," she said.

The hopes of many voters were simpler.

"May God help our children not to kill and steal from each other," said 62-year-old pensioner Jamillya Karashova. "We want peace on our soil. And maybe just a little happiness."