BAKU : Azerbaijani President Ilham Aliyev on Wednesday was set to romp home to a crushing victory in presidential elections denounced by the opposition as a fraud, with exit polls giving him well over 80 percent of the vote.

Several exit polls published after voting ended put Aliyev on over 80 percent, far ahead of main opposition challenger Jamil Hasanli in second place on no more than 10 percent.

Even prior to the close of voting, Hasanli's election campaign alleged that there had been "massive" electoral violations across the country and pledged not to accept the result.

The 51-year-old Aliyev came to power in a disputed 2003 vote after the death of his powerful father Heydar, a former KGB officer and Communist-era boss who ruled the ex-Soviet nation of 9.5 million people for the preceding 10 years.

He was re-elected in 2008 with 89 percent of the vote in a poll called neither free nor fair by Western observers and pushed through a referendum a year later that allowed him to run this time round.

Aliyev, who has a vice-like grip over most media in the country, has stayed away from televised debates and passed up public rallies ahead of the polls. Those backing him argue that his record speaks for itself.

An initial exit poll from the officially-accredited Prognos agency put Aliyev on almost 84 percent of the vote, far ahead of Hasanli, in second place with around eight percent.

As of 5pm (1200 GMT) - two hours ahead of the end of the vote - the central election commission said that more than 66 percent of the country's roughly five million registered voters had cast their ballots.

"We cannot but be pleased by the high level of voter participation," election commission head Mazahir Panakhov said during voting.

While he said the election had generally gone smoothly, Panakhov stated there had been some "provocative" acts, including by the opposition, aimed at disrupting the vote at a small number of polling stations.

'Massive violations across the country'

Main challenger Hasanli, however, has rubbished the election - alleging a string of violations, including voters being bussed round to cast ballots at multiple polling stations, vote-stuffing and observers being barred from monitoring the vote.

"Massive violations were carried out across the country," the Hasanli campaign said in a statement.

The Hasanli camp "does not accept the election result or recognise it as free or fair," the statement said.

Fuelled by billions of petrodollars, living standards in the mainly Muslim nation have soared in the past decade, with Azerbaijan becoming an increasingly important energy supplier to Europe and an ally of NATO.

At one polling station in Baku - a city which has undergone a glitzy building boom in recent years - voters waited in silence to cast their ballots under an Azerbaijani flag.

"Under his (Aliyev's) leadership the country has really developed," aid Rizvan Samedov, a 25-year-old marketing director.

But not all said their country was on the right track.

"I have lost faith in the current leadership," said Samaya Alekperova, a teacher, adding that she would vote for the united opposition candidate.

Normally fragmented, Azerbaijan's weakened opposition - much of which boycotted the 2008 poll - in May seemed primed for a genuine challenge after rallying around a single candidate, but have faced major obstacles getting their message heard.

Hasanli, who has attracted thousands of supporters to rallies, has pledged to step down after two years if elected and switch Azerbaijan to a parliamentary system.

Rights groups accuse the authorities of an intense clampdown on dissent ahead of the election, including the jailing of scores of critics on charges the opposition say are trumped-up.

"It's hard to keep up with the sheer number and the speed at which dissenters are being persecuted at the moment," said John Dalhuisen, Amnesty International's Europe and Central Asia Director.

Aliyev is expected to continue treading a cautious path between the West and Russia after his expected victory, ensuring that Azerbaijan remains a key energy source for Europe and a US ally while not upsetting its giant northern neighbour Russia.

Preliminary partial results are expected out overnight.