Voters in Chile went to the polls on Sunday in an election to decide who will be the country's next president.

Polling stations opened at 8:00 a.m. local time (1100 GMT) and closed at 6:00 p.m. (2100 GMT).

Past surveys suggested former president and billionaire Sebastian Pinera was most likely to win after claiming the largest share of votes in the first round.

But a last-minute surge in support for the center-left candidate, Senator Alejandro Guillier, means the result is far from certain. 

"The election will probably come down to a difference of less than 20,000 votes," political scientist Marcello Mella said.

"This is the most uncertain election since the return of democracy" said Marco Moreno, an analyst at Chile's Central University.

Whoever wins will take office from March 2018 until 2022.

Not promising heaven

Pinera, 68, has painted himself as the most experienced candidate to revive Chile's flagging economy. He's pledged to spur growth in the world's top copper producer by cutting taxes on businesses and launching a $14 billion (€12 billion) spending plan that includes fresh investments in infrastructure.

"I'm not promising heaven and earth, but I promise that Chile will grow robustly," he said in a debate this week.

The Harvard-educated businessman, who ended his 2010-2014 presidential term with a low popularity rating, has sought to capitalize on broad discontent with outgoing center-left President Michelle Bachelet, who has struggled to make good on promises to reform labor and education.

Guillier, 64, wants to continue Bachelet's plan to increase corporate taxes, overhaul education and labor, reform the constitution and improve the pension and health care system. 

Bachelet, who cannot try for re-election, urged citizens to use the nation's 43,000 polling stations as she cast her ballot.

Close race

Pinera won 36 percent of the vote in the first round in November, while Guillier garnered just 22 percent — the weakest result for a center-left candidate since Chile's return to democracy in 1990.

Far-left candidate Beatriz Sanchez performed better than pollsters had anticipated, finishing in third place with 20 percent.

Supporters of Sanchez - one of six candidates who did not make it to the second round - may now choose to back Guillier.

Unlike in many other Latin American countries, voting is no longer mandatory in Chile. Around 14 million people are eligible to cast ballots. 

"Not coming to vote is handing a victory to the powerful elite. We can keep fighting for a more just Chile," Guillier said at his closing rally on Thursday.

Polling booths close at 6 p.m. local time, with official results expected shortly afterward. 

nm, ipj/ng (AFP, AP, Reuters)