Belarussians are set to head to the polls to cast their vote in presidential elections all but certain to re-elect incumbent Alexander Lukashenko for a fifth term.

Voting begins at 05:00 GMT and closes at 17:00 GMT, with the first exit polls expected on Sunday evening.

Lukashenko's re-election five years ago led to mass protests and the imprisonment of leading opposition figures, but support for his 20-year-old government has risen after he cast himself as the guarantor of stability in the face of an economic crisis and a pro-Russian separatist conflict in neighbouring Ukraine.

The West has long ostracised Lukashenko, 61, describing him as the "last dictator in Europe" over his human rights record and his clampdown on political dissent, and has imposed economic sanctions on some Belarussian officials and companies.

Nevertheless, his criticism of Russia's annexation of Ukraine's Crimea peninsula last year, his hosting of Ukraine peace talks, and his pardoning of six opposition leaders in August suggest he is seeking to improve his image in the West, observers say.

The European Union will lift its sanctions on Belarus, including those on Lukashenko, for four months after Sunday's vote, barring any last-minute crackdown, diplomatic sources said on Friday.

The proposal has raised an outcry from those opposition leaders who have spent their lives protesting against the president and promoting Western democracy.

Opposition leader Mikola Statkevich, who was pardoned in August after spending five years in jail, told the AFP news agency: "If they [the EU] are together with this murderer, this criminal, then democracy is just words."

A larger export market would be welcome to Belarus, whose economy has been battered this year by a slump in the currency of Russia, a key trading partner and source of remittances from migrant workers.

Belarus's gross domestic product shrank by 3.5 percent from January to August and the average monthly wage has fallen by about a third in dollar terms since the start of the year to $420.

'There will be no surprise'

None of the three candidates running against Lukashenko in Sunday's poll represent a serious challenge to his rule, and opposition figures have called for a boycott of the election.

On Saturday, the Belarussian dissident Svetlana Alexievich, who has just won the 2015 Nobel Literature Prize, said the EU should be wary of Lukashenko.

"Every four years, new European officials come to power and think they can solve the Lukashenko problem without knowing that he is a man who is untrustworthy," Alexievich told a news conference in Berlin on the eve of the election, which she claims will be rigged.

"No one doubts that Lukashenko will win ... We all suspect that for Lukashenko, it doesn't matter how we will vote, what is important is those who will count the ballots, and so there will be no surprise," she said.

At an unauthorised opposition rally on Saturday in Minsk, the Belarussian capital, also attended by Statkevich, opposition leader Vladimir Neklyayev urged the EU to stand firm against Lukashenko.

"We know one thing: With Lukashenko in power, the situation will never change," he said.

Neklyayev was jailed in 2010 following large street protests over Lukashenko's disputed poll victory.

The opposition figures leading the demonstration linked arms at the head of a column of about 400 protesters and urged the crowd to boycott the vote, while demonstrators shouted slogans such as: "Sasha, leave!", referring to Lukashenko, and some waved EU flags.

Neklyayev added that the rally had only attracted a relatively small turnout because "people are just afraid".

The West will be closely watching Sunday's polls, to be monitored by international OSCE observers, but the main opposition says Lukashenko has already falsified the ballot by barring its leaders from standing.

Lukashenko instead stands against three virtual unknowns, only one of whom, Tatiana Korotkevich, has bothered to run a campaign.

By providing the only alternative for opposition supporters, 38-year-old Korotkevich has made a strong showing in opinion polls, but even her team doubts she could push the election into a second round.

While Lukashenko did not officially campaign, he is in any case ubiquitous on state media.

Source: Agencies