Michel Martelly, a popular singer-turned-politician, will be Haiti's next president, the Caribbean nation's electoral council announced at a Monday news conference.

Martelly, a political rookie who had been given virtually no chance to win the March 20 runoff vote, easily defeated former first lady Mirlande Manigat. The performer known as "Sweet Micky" received nearly 68 per cent of the votes, electoral council spokesman Pierre Thibault said.

Manigat led the first round of voting in November that winnowed a field of 18 candidates down to two for the runoff. But in December, much of the country was paralyzed by riots after the electoral council announced first-round results that initially excluded Martelly from the runoff.

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Michel Martelly gestures to supporters after voting during the presidential runoff in Port-au-Prince on March 20. ((Associated Press/Ramon Espinosa))

The Organization of American States later determined those results were incorrect and the musician had come in second, giving him a spot on the second ballot.

The final results, allowing for a period of appeals, are expected April 16. If the results hold up, Martelly will take office in mid-May, after President René Préval, who could not seek another term under the constitution, steps down.

Martelly, a star of the Haitian genre known as compas, is a "total outsider" who had trouble finding a party to run for when he announced his decision to seek the office, the CBC's Connie Watson reported from Port-au-Prince, the capital, but his lack of political experience turned out to be an asset in a country where the government has provided few services and corruption runs deep.

Martelly promised profound change for Haiti, vowing to provide free education in a country where more than half the children can't afford school and to create economic opportunity amid almost universal unemployment.

However, he will face a challenging environment that includes a Senate and Chamber of Deputies controlled by Préval's party and widespread anger over the slow progress of reconstruction from the January 2010 earthquake that the government says killed an estimated 300,000 people. Haiti is also grappling with a cholera outbreak that has killed more than 4,000 people since October and is expected to worsen with the spring rainy season.

"He doesn't have any kind of backing in parliament. It's controlled by Préval," said Yves Colon, a journalism professor at the University of Miami who follows Haitian politics.

"It makes me wonder how he'll be able to achieve anything with that kind of dynamics. Proposed laws could be held up or not even brought up for a vote."

However, there is an estimated $10 billion in foreign aid that donor nations have delayed while they awaited the outcome of the election, Watson reported, and Martelly appears to be in a good position to get those taps open.

Thousands of Martelly supporters poured into the streets of Port-au-Prince on Monday, carrying Martelly posters, climbing on cars and cheering loudly.

"Today is a big day for me," Jeanor Destine, 22, said as he ran through the streets. "We're finished with the old government and want to bring in a new government. We've been through so much misery. That's why we're supporting Martelly."

"I'm going to celebrate with the people, then I'm going home to  my kids," Wilson Goren, a 32-year-old street vendor, said as fireworks erupted around him after the results were announced.

His campaign posted in Creole on Twitter: "Thank you for your confidence. I bloom for all my people. We're going to work for all Haitians. Together we can."

An electoral council official, Serge Audate, said about 15 per cent of the tally sheets had problems suggesting possible fraud and had to be quarantined. One problem was tally sheets showed more voters cast ballots at a polling centre than were registered, he said.

"We have a team of lawyers who are going to study that," Audate said.

With files from the CBC's Connie Watson and The Associated Press