PHNOM PENH - Cambodia's strongman premier Hun Sen looked set to extend his 28-year rule Sunday in elections marred by allegations of widespread irregularities and the exclusion of the opposition chief.
The former Khmer Rouge fighter turned prime minister appeared so confident of victory that he did not even bother to personally campaign.
Hours after polls opened, the opposition decried what it described as the kingdom's worst ever vote irregularities.
"The situation is more serious than at any previous election," Cambodian National Rescue Party spokesman Yim Sovann told AFP.
He said many names had disappeared from the electoral roll while thousands of people could not vote as someone else had already used their ballot.
The ink used for voting could also be easily washed off, he added.
Hundreds of people protested at one polling station in eastern Prey Veng province against alleged irregularities, a witness told AFP by telephone
But the National Election Committee denied the accusations.
"There is no problem of names missing from the lists," NEC secretary general Tep Nytha told AFP.
Even before polls opened, the opposition had warned that a Hun Sen win would be "worthless" without the participation of its leader Sam Rainsy.
The French-educated former banker returned to Cambodia on July 19 from self-imposed exile after receiving a surprise royal pardon for criminal convictions which he contends were politically motivated.
But he is barred from running as a candidate since the authorities said it was too late to add his name to the electoral register.
Rainsy toured polling stations in the capital Phnom Penh on Sunday to "collect more evidence" of vote irregularities.
He said that if indications pointed to a "plot to rig the election" then "definitely we will protest".
The CNRP said earlier that it had uncovered irregularities such as tens of thousands of duplicated voter names that would allow some people to cast ballots twice.
Local poll monitor the Committee for Free and Fair Elections in Cambodia alleged that up to 1.25 million people who are eligible to cast ballots are not on the voter lists.
Polls opened at 7:00 am (0000 GMT) and close at 3:00 pm, with about 9.6 million people registered to vote - more than one third of whom are below the age of 30.
A spokesman for the Cambodian People's Party told AFP the party was confident of another landslide.
"We expect to keep an absolute majority," Khieu Kanharith said.
A smiling Hun Sen kissed his ballot and dropped it into the box at a polling station at a teacher training school in the town of Ta Khmao near the capital Phnom Penh.
First in line to vote there was 87-year-old Yim Hor Eam who described it as a "historic day".
"I voted for peace for the country. If we make a wrong decision, the country will be in danger, will be destroyed," he told AFP, without revealing who he supported.
Hun Sen oversaw Cambodia's transformation from a nation devastated by the "Killing Fields" genocide era to become one of Southeast Asia's most vibrant economies.
The 60-year-old premier - who has vowed to rule until he is 74 - is regularly accused of trampling on human rights and quashing political dissent.
And while garment exports and tourism have brought double-digit economic growth, Cambodia remains one of the world's poorest countries.
For decades, Hun Sen's simple message - that he and the CPP liberated Cambodia from the Khmer Rouge and ushered in decades of peaceful development - has been enough to guarantee support.
"Hun Sen has been adept at humiliating his political opponents by stripping opposition deputies of their immunity and orchestrating the exile of Sam Rainsy," said Cambodia expert Carl Thayer, a professor at the University of New South Wales in Australia.
But he is "also a genuinely popular figure", he added.
"Because the opposition lacks deep and widespread support in the provinces their best prospect is to reduce the number of seats held by the CPP."
The ruling party now has 90 seats in the 123 seat National Assembly.
There are tentative signs of change as social media allow the opposition to reach out to young, urban voters.
Thousands of opposition supporters have turned out in recent weeks for campaign rallies chanting "change!"
While the opposition hopes that Sunday's election will be a step at least towards a shift in power, the strongman premier appears to have other plans.
His three US-educated sons have been handed top party or army positions and the youngest is running in Sunday's election, fuelling speculation they are being groomed to replace him.