Costa Rica has elected its first female president in a landslide victory, marking another political milestone for women in Latin America.

Laura Chinchilla, from the centrist ruling party, won 47% of the vote in a crowded field in yesterday's poll, further eroding the region's reputation as a bastion of machismo and patriarchy.

"Wives and working women continue overcoming barriers to make a greater Costa Rica," the 50-year-old said in her acceptance speech. "All the women and also the men who have accompanied us have made it possible that a daughter of this country can today be president."

Chinchilla is the fifth woman to be elected president in Latin America in the past two decades, a sign of slowly growing female economic and political clout after centuries of subservience.

She followed Argentina's Cristina Kirchner, elected in 2007, Chile's Michelle Bachelet, elected in 2006, Panama's Mireya Moscoso, elected in 1999, and Nicaragua's Violeta Chamorro, elected in 1990.

Chinchilla, married and mother to a teenage son, is a protege of President Óscar Arias, a Nobel peace laureate and veteran political operator who has consolidated Costa Rica as one of central America's most stable, prosperous economies.

She stepped down as vice-president last year to run as his successor and promised to keep the ruling National Liberation party's free market policies of expanding trade deals and wooing investment.

"I am thankful for the good work of the outgoing government and thankful our country is again moving forward and refuses to allow this advance to stop," Chinchilla told cheering supporters.

A social conservative who opposes gay marriage and abortion, she campaigned under the slogan "Laura: firm and honest," and said her priority would be to combat drug-fuelled violent crime. Opponents had cast her as a hypocritical Arias puppet who was soft on criminals. One rival, Otto Guevara, took a televised polygraph test to show he was more honest. Another, Luis Fishman, ran on the slogan that of all the candidates he was the "lesser evil".

Despite or perhaps partly because of such tactics, Chinchilla won in all seven provinces, a rare feat, and easily surpassed the 40% needed to avoided a run-off.

She will not have an easy ride. Environmentalists oppose the president-elect's commitment to open-pit mining, trade unions resent a free trade deal with the US and opposition parties may have enough votes in congress to impede her fiscal and energy policies.

Girls and women are getting better education and jobs across Latin America but patriarchy remains entrenched, according to a recent poll taken in 18 countries. Some 36% of respondents said women should stay at home rather than work, the same proportion as in 1997.