SAN JOSÉ: A conservative Christian congressman best known for his opposition to rights for same-sex couples remains the favourite in Costa Rica’s presidential election next month, according to a poll released on Tuesday night.

Fabricio Alvarado, a 43-year-old ex-television host and the only lawmaker from the National Restoration party, led in several run-off scenarios in the January 29-30 survey conducted by OPol Consultores.

Election experts say a second-round run-off is likely as no candidate is expected to win at least 40% of the vote in the February 4 election.

A run-off featuring the top two vote-getters would take place in early April.

In a hypothetical match-up against Antonio Álvarez of the National Liberation Party, Alvarado would win with 37% support compared to Alvarez’s 34%, according to the poll.

The OPol Consultores poll has a margin of error of 3.3%.

Alvarado has even larger leads in potential run-offs with other candidates, including conservative lawyer Juan Diego Castro of the small National Integration Party and Carlos Alvarado, the candidate from President Luis Guillermo Solís’ ruling Citizens’ Action Party.

Alvarado gained momentum in the race after he expressed his strong opposition to a January ruling by the Inter-American Court of Human Rights, which called for the legalization of same-sex marriage.

Costa Rica is one of the more prosperous and stable countries in Central America. It had been ruled by a two-party dynasty until an upset in the 2014 vote that brought to power Solis, a centre-left academic who had never held elected office.

Under Costa Rican law, Solís is barred from seeking immediate re-election.