Woman casts her vote in a polling station during presidential election in Tunis. Photo: REUTERS/Muhammad Hamed.

Tunis - Tunisians were voting on Sunday in a hotly contested presidential election seen as crucial for enhancing nascent democracy in the country roiled by economic woes and violent militancy.

Authorities said they had deployed around 100,000 security personnel to secure polling stations across the country, which has experienced a string of terrorist attacks in recent years, mostly claimed by Islamic State militants.

Around 7.2 million people are registered to vote in around 4,567 polling stations across Tunisia.

Voting started as scheduled at 8 am (0700 GMT) in 4,325 polling stations, where it will run for 10 hours, the head of the election commission, Nabil Baffoun, said.

The rest of the polling stations, located in border areas, were to open two hours later and close at 1600 (1500 GMT) due to security reasons, Baffoun added, according to the state news agency TAP.

Twenty-six contenders are competing in the polls, Tunisia's second democratic presidential vote since the 2011 uprising that toppled long-time autocrat Zine El Abidine Ben Ali.

Top candidates include incumbent Prime Minister Youssef Chahed, the deputy head of the influential Islamist Ennahda movement, Abdelfattah Morou, and former defence minister Abdelkarim Zbidi.

Also running is media magnate Nabil Karoui, who was arrested last month on charges of money laundering and tax evasion.

Two female candidates - former tourism minister Salma Loumi and politician Abeer Mousa, seen as a loyalist of Ben Ali - are also standing.

The day before the election, two of the 26 candidates - Slim Riahi and Mohsen Marzouk - said they were pulling out in favour of Zbidi, who is running as an independent.

However, the withdrawals have made no legal change to the number of presidential hopefuls, according to experts.

Tunisia's presidential elections, originally scheduled for November, were pushed forward after the country's first democratically elected president, Beji Caid Essebsi, died in July, five months before the end of his term.

If there is no outright winner in the vote, there will be a second round, the specific date of which has not been set yet.

Official results are expected by Tuesday.

Tunisia, the birthplace of the Arab Spring revolts, is widely seen as the sole democratic success story of the 2010-11 uprisings.

The North African country has struggled with an economic slowdown, social unrest triggered by the 2011 revolt, and subsequent extremist attacks.

Tunisia has been under pressure from international lenders, mainly the International Monetary Fund (IMF), to take drastic measures to revamp its economy.

The IMF, which in 2016 approved a four-year loan of about 2.8 billion dollars for Tunisia, said this year that Tunisia's economy had improved since 2017.

However, Tunisia still needs to decrease its fiscal and external deficits and reduce inflation.

The country's unemployment rate stands at 15.3 per cent.

dpa