DUSHANBE (Reuters) -- Tajik leader Imomali Rakhmonov, all but certain to win a presidential election on Monday, sought to pre-empt Western criticism by saying it was too early to expect his Central Asian nation to hold a democratic vote.

In power since 1992, Rakhmonov has been criticized by the opposition and Western observers for failing to organize a fair contest in his ex-Soviet state. Tajikistan has never held an election judged free and fair by Western monitors.

Rakhmonov, who joined Tajikistan's 3.2 million eligible voters to cast his ballot on Monday, said his country's vision of development was different from that of the West.

"More than 99 percent of people in Tajikistan are Muslim. We have a completely different culture," Rakhmonov told a crowd of reporters and monitors from the Organization for Security and Cooperation in Europe after voting in the capital Dushanbe. "You have to take that into account. It would be absolutely wrong to say that this election will be 100 percent in line with OSCE standards. ... We are developing but there are problems."

Rakhmonov, who won the last election in 1999 with 96.4 percent, has been derided for cracking down on civil rights and jailing dissidents in the country where two thirds of the 7 million population live below the poverty line.

Opposition parties are boycotting the election in protest, saying it is no different from staged Soviet-style elections. Three opposition activists were arrested after holding a street protest over the weekend.

Leaders of ex-Soviet states are sensitive to criticism of elections in their countries after popular protests brought new, pro-Western politicians to power in Georgia and Ukraine.

"Do you think democracy is all about revolutions, blood, instability? You think this is democracy? No," Rakhmonov told reporters.

Yet, the mood was calm in Tajikistan as voters cast their ballots across the mountainous nation which is still recovering from a brutal civil war in the 1990s that killed tens of thousands of people.

Rakhmonov's four rivals in the election are officials from state-friendly parties, a line-up condemned by the opposition as an attempt to create a semblance of a democratic contest.

The 54-year-old leader has changed the constitution to allow himself theoretically to stay in power until 2020.

Although there was no doubt about Rakhmonov's victory, the West is watching the election closely as instability in Tajikistan, a close U.S. ally in its war on terrorism, could spill over to the wider Central Asian region.

One Western observer told Reuters his delegation had registered cases of ballot stuffing, additional voter lists and other irregularities just hours after voting started.

Yet, Rakhmonov appears to be genuinely popular as Tajiks link him to stability in their country after years of war. "I voted for Imomali Sharipovich (Rahmonov)," said Faizali, a 63-year-old resident of Dushanbe wearing a traditional black-and-white skull cap. "He has done a lot for us. Voting for him means voting for peace."