While current President Andray Rajoelina, who seized power in a 2009 coup, isn't on the ballot several of his proxies are, The Wall Street Journal reported.
South Africa and other regional powers persuaded Rajoelina, 39, a former nightclub disc jockey, not to seek re-election, but he and other former leaders of the commodity-rich island have proxies in the race, observers said.
"The credibility of the poll will be crucial as it will determine whether foreign financial assistance is resumed or not," Isaac Matshego, an economist at Nedbank in Johannesburg, South Africa, told the Journal.
To win Friday, a candidate must garner more than half of the vote. Because support for Rajoelina and former President Marc Ravalomanana seems spread across multiple candidates, the top two vote-getters likely will have to have a runoff in December, Philippe de Pontet, Africa director for the consultancy Eurasia Group, said.
De Pontet said three candidates are running with Rajoelina's backing, including Hery Rajaonarimampianina, who stepped down as finance minister to focus on the campaign.
Ravalomanana, living in exile in South Africa, entered his wife in the race at first, but African leaders balked. The former president then threw support to Jean Louis Robinson, who was health minister during Ravalomanana's presidency.
Robinson has said he would install Ravalomanana's wife as prime minister if he wins. Rajaonarimampianina has said he would do the same for Rajoelina.
Madagascar is rich in vanilla, rosewood and rare animals that draw tourists to the tropical island off the African coast. The African Growth and Opportunity Act, which allows many African countries to send duty-free exports to the United States, helped establish a booming textile industry in Madagascar.
In 2009, Rajoelina, who was mayor of the capital, Antananarivo, at the time, began a campaign accusing the Ravalomanana administration of fueling inflation and corruption. Violence saw hundreds of people die before the military-backed Rajoelina was installed as president and sent the island's economy into a tailspin.
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