Portuguese voters will head to the polls to choose a president on Sunday, with the dramatic context of a coronavirus lockdown creating more headlines than the expected re-election of incumbent Marcelo Rebelo de Sousa.

The country of 10 million people has this week been breaking daily records in virus death tolls, with 221 fatalities in 24 hours announced Thursday by the national health authorities.

On Wednesday, Portugal hit a record 14,647 new cases in one day.

The explosion in new infections is mainly the result of the spread of the more contagious variant strain first discovered in Britain.

In view of the troubling figures, and the imposition of a second national lockdown last week, the traditional last round of political campaigning on Friday has been scrapped.

There is no possibility of postponing the vote, and candidates and observers fear a record-low voter turnout -- casting doubt on pre-election polls forecasting a first-round win for Rebelo de Sousa.

In a bid to boost participation among the 9.8 million registered voters, including 1.5 million abroad, the electoral authorities last Sunday organised an unprecedented early voting day.

Teams of volunteers even went door-to-door to collect ballots from about 13,000 people quarantined or confined to retirement homes.

Around 200,000 voters answered the early-vote call, but press pictures of long queues outside some polling stations, especially in the capital Lisbon, offered little reassurance about the infection risks.

- Second round ? -

Seven candidates are in the running for president. The position confers little political power. though the incumbent can dissolve parliament to call early elections.

The president is elected by universal suffrage for a maximum of two five-year terms. The conservative incumbent Rebelo de Sousa has been widely expected to win re-election in the first round of voting, but some observers see the unusual backdrop of a pandemic as muddying the waters slightly.

"A year ago, this election seemed like a cake walk," for the president, a 72-year-old former teacher, "but it might not be that simple," cautions Paula Espirito Santo, of the University of Lisbon.

"It would only take a 70 percent abstention rate to make a second round almost inevitable," Rebelo de Sousa said this week, seeking to highlight the stakes.

His four predecessors, since the adoption of a democratic constitution in 1976, have all served two terms.

Rebelo de Sousa has remained popular since being elected in 2016, cohabiting happily with Socialist Prime Minister Antonio Costa, whose party hasn't bothered to put up a presidential candidate as it saw no chance of victory.

- Populist challenger -

Faced with such low expectations from the opposition, the president may have trouble mobilising his supporters, especially as some on the right accuse him of having been too conciliatory towards the government, which came to power with the help of the radical left shortly before him.

Right-wing populist candidate Andre Ventura, the 38-year-old founder and head of the anti-establishment party Chega ("Enough"), is hoping for a strong showing on Sunday.

His party entered parliament for the first time after last year's legislative elections, winning 1.3 percent of the popular vote.

Opinion polls show he himself could score around 10 percent of the presidential vote. 

That would be "an excellent result," for Ventura, political commentator Antonio Costa Pinto, of Lisbon University, told AFP.

The majority of polls place him third, or vying for second with former socialist MEP Ana Gomes. 

Gomes, a career diplomat, is an anti-corruption activist and strong critic of the Socialist prime minister.