RIGHTWINGER Laura Fernandez claimed victory in Costa Rica’s presidential race today after preliminary results gave her a commanding lead and her closest rival conceded defeat.

Partial results from Sunday’s election showed Ms Fernandez, the chosen successor of President Rodrigo Chaves, securing a first-round win and avoiding a run-off in a crowded field.

With votes counted from 93.7 per cent of polling stations, the Supreme Electoral Tribunal said the Sovereign People’s Party candidate had 48.3 per cent of the vote.

Her nearest challenger, economist Alvaro Ramos of the National Liberation Party, trailed on 33.4 per cent and conceded on Sunday night, pledging to lead a “constructive opposition.”

Ms Fernandez will not be formally declared president until a manual vote count begins on Tuesday.

Speaking after Mr Ramos’s concession, she said voters had backed “deep and irreversible” change and a continuation of reforms.

Crime dominated the campaign in the historically peaceful nation, where violence has surged in recent years.

Ms Fernandez, a former planning minister and minister of the presidency, campaigned on extending Mr Chaves’s confrontational style as the best way to address the crisis.