SAN JOSE: Laura Chinchilla was on course to become Costa Rica's first female president and only the fifth ever in Latin America, preliminary results from the election commission indicated.

Chinchilla, the ruling party candidate, won 47.6 percent of the first 20.1 percent of votes counted, more than 20 percentage points ahead of her main opponents, and above the 40 percent needed to avoid a run-off.

Center-left opposition candidate Otton Solis won 23.15 percent of the votes counted, in second place, and right-wing lawyer Otto Guevara garnered 21.85 percent.

Solis, who lost by a whisker to current President Oscar Arias in 2006, already accepted defeat at that point.

"With a lot of respect, we accept the reality," Solis told a gathering of his followers.

The opposition had criticized Chinchilla as being a puppet of Arias, and she was expected to continue his policies of promoting free trade and international business ties.

The 50-year-old served as vice president under Arias and is socially conservative on issues such as abortion.

Her National Liberation Party (PLN) bet on her past experience as public security minister and justice minister to win voters over on the issue of crime issue, a key concern for voters.

Balloting took place calmly throughout Latin America's oldest democracy, which has no army, amid fears of high abstention rates.

Abstention was at 33.43 percent, according to initial results, of some 2.8 million eligible to vote for a new president, two vice presidents, as well as 57 lawmakers and municipal leaders.

The elections again tested the organizational skills of the PLN, which has dominated politics in Costa Rica for the past six decades, despite the emergence of new parties in recent years.

Solis, an economist from the Citizen's Action Party, the biggest opposition grouping, had lagged behind Guevara in pre-election surveys.

Guevara, a 49-year-old lawyer who founded the pro-business Libertarian Movement Party, had proposed changing the currency to the dollar, and more free trade deals for the country currently negotiating a deal with China, after switching allegiance from Taiwan in 2007.

He also called for change to end corruption, following several scandals in recent years.

Former president Rafael Angel Calderon pulled out of the campaign after receiving a five-year prison sentence for corruption.

Some 200 international observers oversaw the elections, and children helped thousands of volunteers aiding the process, which Arias called "a multi-colored party."

He is due to hand over to the new president on May 8.