Mexico City: Costa Rica's centre-left presidential hopeful Carlos Alvarado Quesada took an insurmountable lead in a presidential runoff on Sunday, winning 61 per cent of the vote in a race that exposed deep divisions in the country over religion.

Costa Rica's electoral council announced the preliminary result with 91 per cent of polling stations counted.

Successful presidential candidate Carlos Alvarado talks to the press after voting in the presidential runoff election in San Jose, Costa Rica, on Sunday, Credit:AP

Voters had the choice of a conservative Protestant singer, Fabricio Alvarado Munoz, as their president, representing a potential sharp turn from the country's embrace of gay rights.