Dominican Republic voters went to the polls Sunday to elect their next leader in a closely-fought race between ruling party-backed economist Danilo Medina and former president Hipolito Mejia.

Medina, 60, is representing the Dominican Liberation Party (PLD) of outgoing President Leonel Fernandez, who has served three terms in office. The president's wife, Margarita Cedeno, is Medina's running mate.

Mejia, 71, of the Dominican Revolutionary Party (PRD), governed from 2000 to 2004 in this Caribbean nation of 10 million inhabitants, which shares the island of Hispaniola with Haiti.

Also on the ballot are four other candidates given slim chances of having much of an impact on Sunday's vote.

Opinion polls predicted a tight race, and a second round election will be held in June if no candidate claims at least 50 percent of the vote.

Altagracia Rosario arrived early at her local polling station at a precinct just outside Santo Domingo.

"I came because I want to be a good citizen and voting is a civic duty," she said.

Balloting began nationwide at 1000 GMT and was due to end at 2200 GMT, with the key campaign issues being the high cost of living, unemployment, corruption and a soaring crime rate.

Economic inequality is another major concern for many of the election's 6.5 million registered voters, including 328,000 who live abroad, about a third of them in New York.

The Dominican Republic side-stepped the global economic crisis in 2008 but remains mired in poverty despite solid economic growth under Fernandez.

Clashes between the candidates' supporters have left two dead in recent weeks, and the Supreme Electoral Tribunal has had to admonish both candidates to tone down their rhetoric.

A Greenberg poll published early in the week gave Medina 51 percent of likely votes, compared to 46 percent for Mejia. Such a tight margin could leave four minor candidates splitting the few remaining points.

A Gallup poll in late April meanwhile gave Medina 51 percent and Mejia 44.6 percent.

The fact that President Fernandez's wife is Medina's running mate reinforces his image as a candidate who will see through the current government's liberal economic policies, promising "safe change."

The mountainous nation still depends heavily on tourism, remittances from Dominicans living overseas, aid from the International Monetary Fund and cheap oil from Venezuela.

Inflation surpassed seven percent in 2011, unemployment was 14.6 percent and 30 percent of its people live in poverty.

Mejia has shaped his campaign around promises to fight poverty with social programs and policies to boost agriculture and aid farm workers.

An agronomist by training, Mejia has a strong following among poor farmers, with a down to earth style and rhetoric that helped him win the presidency in 2004, when he defeated Medina.