Honduran presidential candidate Xiomara Castro headed for a landslide win in Sunday's election, declaring victory as supporters danced outside her offices to celebrate the left's return to power 12 years after her husband was ousted in a coup. With half the ballots counted, Ms Castro, the wife of former President Manuel Zelaya, held a nearly 20-point lead over Nasry Asfura, the capital's mayor and ruling National Party hopeful, who won 34 per cent according to a preliminary tally on Monday. Jubilant celebrations broke out at Castro's campaign headquarters as the vote count poured in and her lead held up. The offices of Asfura's ruling conservative National Party were deserted. Victory for Ms Castro would end a dozen years of conservative rule, and return the Honduran leftists to power for the first time since Mr Zelaya was deposed in a 2009 coup. Both the National Party and Ms Castro's Liberty and Refoundation (Libre) party had claimed victory after what the electoral council said was a historic voter turnout on Sunday. "We have turned back authoritarianism," she told supporters late on Sunday, surrounded by her Libre Party faithful, aides and family, including her husband Mr Zelaya, who was ousted when business and military elites allied against him, ushering in a dozen years of National Party rule. Business leaders quickly offered congratulations and Ms Castro promised to work "hand in hand" with the private sector. "We're going to form a government of reconciliation, a government of peace and justice," Ms Castro added. More than 5.1 million Hondurans were registered to vote at nearly 6,000 polling stations across the country. In addition to a new president, they chose a new congress, new representatives to the Central American Parliament and local officials. Ms Castro sought to mount a unified opposition to departing President Juan Orlando Hernandez, who has denied accusations of links to powerful gangs, despite an investigation in the United States linking him to alleged drug trafficking. After allying with the 2017 runner-up, a popular TV host, most polls had reinforced her status as clear favourite. "We can't stay home. This is our moment. This is the moment to kick out the dictatorship," Ms Castro said after voting in the town of Catacamas. She said she trusted that voters would report any problems they see and that international observers would also help to ensure a fair vote. <i>With reporting from agencies</i>