QUITO, Ecuador (AFP)— Car horns in Quito blazed in celebration on Sunday as a partial vote count suggested banana empire heir Daniel Noboa, 35, could become the youngest-ever president of violence-riddled Ecuador.

Ecuadorans voted for 10 hours Sunday with no reports of violence in a country gripped by a bloody drug war and a rash of political assassinations that cut short the bid of a popular candidate.

With 87 per cent of votes counted, the electoral authority said Noboa had a lead of 52 per cent over his socialist rival, 45-year-old lawyer Luisa Gonzalez.

Some 100,000 police and soldiers were deployed to keep the vote safe and Noboa and Gonzalez cast their votes in bulletproof vests just weeks after a rival was murdered.

Both candidates have vowed to prioritise dealing with the escalating violence.

"May we elect the best president because (he or she) will govern a country that is destroyed... to address all these problems such as insecurity," Indigenous voter Ramiro Duchitanga told AFP in Cuenca in Ecuador's south.

"It is a critical election," Freddy Escobar, a popular 49-year-old singer, told AFP in a voting line, citing crime as his main worry. "I am voting in fear, not knowing what will happen."

After images on social media showed a person appearing to fill out multiple ballots in favour of Noboa, the head of the National Electoral Commission, Diana Atamaint, promised an "immediate" investigation.

The main concerns of Ecuadorans, according to recent polls, are crime and violence in a country where the murder rate quadrupled in the four years to 2022.

"Today we win," Noboa shouted as he pumped his fist in the air after voting in the coastal town of Olon, where he lives.

Gonzalez also predicted victory as she cast her ballot in the southwest town of Canuto.

"My hunch is that Ecuador will win, in other words, Citizen Revolution," she said, referring to her political party.

Long a peaceful haven between major cocaine exporters Colombia and Peru, Ecuador has seen violence explode in recent years as enemy gangs with links to Mexican and Colombian cartels vie for control.

The fighting has seen at least 460 inmates massacred in prisons since February 2021 -- many beheaded or burned alive in mass riots.

And the bloodbath has spilled into the streets, with gangs dangling headless corpses from city bridges and detonating car bombs outside police stations in a show of force.

In August, the violence claimed the life of anti-graft and anti-cartel journalist and presidential candidate Fernando Villavicencio, mowed down in a barrage of submachine-gun fire after a campaign speech.

He had been polling in second place.

A state of emergency was declared after Villavicencio's assassination, and Noboa and Gonzalez both campaigned, and voted, with heavy security details.

Sunday's winner will be elected to only 16 months in office -- completing the term of incumbent Guillermo Lasso, who called a snap vote to avoid possible impeachment for alleged embezzlement.

They could run again for the 2025-29 presidential term, and the one after that.

Both candidates are relative unknowns, and a win for either would make history: Gonzalez becoming Ecuador's first woman president, or Noboa its youngest.

Gonzalez is the handpicked candidate of socialist ex-president Rafael Correa, who governed from 2007 to 2017 and lives in exile in Belgium to avoid serving an eight-year prison term for graft -- another major concern in the country.

Noboa is the son of one of Ecuador's richest men, who himself has five failed presidential bids to his name.

Ecuador has a poverty rate of 27 per cent, with a quarter of the population unemployed or holding down an informal job.

Opinion polls list unemployment as voters' second concern.

Gonzalez has promised more social spending if she is elected, especially on education and health care, while Noboa has vowed he will ensure "progress for everyone."

From eight candidates, Gonzalez took the most votes in the first round in August with 34 per cent, followed by Noboa with 23 per cent.

Neither Gonzalez nor Noboa will have an absolute majority backing their projects in the legislature, and with only 16 months in office, either would face an uphill battle to push through any reforms, analysts say.

Voting is compulsory for 13.4 million eligible voters in the country of 16.9 million.