Nursultan Nazarbayev, the Kazakh president, has been re-elected to another five-year term, election officials said.

Partial results released by the Central Election Commission on Monday said Nazarbayev secured 95.5 per cent of the votes.

The commission said none of the three other challengers to Nazarbayev had collected more than two per cent of the vote.

However, it said its figures were not final, but did not disclose what percentage of the votes had been counted.

Election observers from the Organisation for Security and Co-operation in Europe have complained about a lack of transparency and competition in the vote.

The margin of Nazarbayev's victory marks an improvement on the 91.2 percent he picked up in his last re-election victory in 2005.

Zhambyl Akhmetbekov, head of the Communist People's Party of Kazakhstan, a pro-government splinter group of the original Kazakh Communist Party, received 1.4 per cent of the vote and pro-government Senator Gani Kasymov 1.9 per cent.

The environmentalist Mels Yeleusizov, who on Sunday said he had voted for Nazarbayev, picked up 1.2 per cent, according to the partial count.

Official voter turnout was said to have been almost 90 per cent, but there were early indications that it had been artificially boosted.

Early voters and 18-year-olds casting their ballot for the first time were rewarded with household goods, such as food blenders and electric kettles, according to the Associated Press.

Nazarbayev, 70, has ruled Kazakhstan unchallenged since the 1980s, when it was still part of the Soviet Union.

He has made stability his main motto and overseen market reforms and more than $120bn in foreign investment since taking office.

Opposition politicians refused to take part in the election, calling for a boycott and describing the vote as a sham.

'Pressured to vote'

Several reports surfaced of university students being pressured into voting by threats of expulsion. Hundreds of students were seen at dawn outside polling stations at the Al-Farabi Kazakh National University in Almaty, which critics said showed that pressure was being applied.

"With this wretched weather, and early on a Sunday morning when you would expect students to lie in ... to see such large crowds is quite unnatural," Vladimir Kozlov, leader of the unregistered opposition Alga party, said.

Election monitors also reported seeing anomalous spikes in turnout figures at polling stations at various junctures of the day.

Nazarbayev's term was to have ended in 2012, but in January he called the early election after a proposal to cancel the next two elections was ruled unconstitutional.

The three rival candidates all openly expressed their support for Nazarbayev and the opposition argued they had been placed in the field by the government to make the vote look legitimate.

One of the candidates, environmentalist Mels Yeleusizov, said he "expressed my respect for the winner" by voting for Nazarbayev.

Only one party, Nazarbayev's Nur Otan, is represented in parliament.

But as he cast his vote in the capital Astana, Nazarbayev insisted Kazakhstan is "an open society and a democratic one".

"All the presidential candidates had an equal opportunity to visit all the regions of our country," he said.

"They had equal access to the media. They expressed their ideas, their thoughts to the Kazakh people."