But international organisations welcomed the conclusion of a tortuously long voting process that began in October 2015 and paralysed political life in this unstable Caribbean nation that is the poorest in the Americas.
Moise was declared winner of the November 20 first round Tuesday night by the Provisional Electoral Council, with 55.6 percent of the votes.
To check against fraud -- the reason for the scrapping of the election the first time Haiti tried in 2015 -- the council said right after the election that 12 percent of the ballots must be verified.
After a week of checking, the council said there was no signficant fraud.
The losing candidates argued that the verification was not done properly.
"Fanmi Lavalas will never accept this electoral coup," said fourth place finisher Maryse Narcisse, referring to her party.
Moise Jean-Charles, the third place finisher, also refused to recognise the result and urged people to stand up and protest.
"Either we mobilise and defend our rights or we accept this electoral coup," he said.
"When the law goes against the people, the people must be outside the law," he said without explaining what exactly he meant.
The runner up, Jude Celestin, has not yet spoken out publicly.
International organisations welcomed the end of the electoral saga, however.
The Organisation of American States said it "commends the conclusion of an electoral process that, despite having been long and complex, has allowed the country to continue down the path of democratic strengthening."
With the losers protesting, the United Nations and ambassadors from countries known as the corp group encouraged all Haitians to recognise the results as announced and "work in a constructive way for the peaceful conclusion of the election cycle."
Moise will take power February 7.