Over 20 million people in Peru are eligible to vote in the country's election [Reuters]

Peruvians are voting in a general election that seems likely to go to a second round run-off.

The compulsory vote began throughout the Andean nation at 8am (13:00 GMT) on Sunday, with almost 20 million people eligible to vote for a successor to President Alain Garcia, the center-right incumbent, who cannot immediately stand again.

The vote sees Ollanta Humala, the left-wing front-runner, square off against three rivals all favoured by big
business.

"Ollanta Humala is a clear front-runner, who has a solid one third of the vote already," Mariana Sanchez, Al Jazeera's correspondent reporting from Lima, said.

"But polls say that no candidate will be able to reach the 50 per cent plus one vote needed to win, so clearly there will be a run-off."

Economic growth

Humala is a former army officer, but he has moderated his tone since narrowly losing Peru's 2006 election race, and has proved popular with low-income voters.

"Although there's an economic boom here, no candidate has made a clear plan about how they plan to tackle poverty," Sanchez said.

"Ollanta Humala is really the favoured candidate because he's the only one who has talked about a fair distribution of wealth."

Behind Humala is Keiko Fujimori, the daughter of former Peruvian President Alberto Fujimori; Alejandro Toledo, a former president; and Pedro Pablo Kuczynski, a former prime minister and Wall Street banker.

An Ipsos poll gave Humala, who leads the Peruvian Nationalist Party, 28.1 per cent of the vote. Keiko Fujimori had 21.1 per cent, according to the poll, suggesting a runoff would be between them.

Fujimori carries with her the legacy of her father's corruption, but many still appreciate the former president for overseeing years of economic expansion and improved infrastructure.

'Democratic convictions'

While President Garcia is prevented by law from running in the election, his ruling American Popular Revolutionary Alliance (APRA) backed Kuczynski on Saturday.

The APRA said Kuczynski had "democratic convictions" that would guarantee the continuation of current government policy.

"Our support is unconditional and we haven't even spoken with [Kuczynski]. We've done this with the country's interests in mind," Jorge del Castillo, an APRA figure, was quoted by the Reuters news agency as saying.

Kuczynski, 72, is known as "El Gringo" because of his European parents and is strongly backed by wealthy voters in the capital, Lima, but may struggle further afield.

If no candidate gets more than 50 per cent of the vote, a second round will be held on June 5.