Pierre-Louis Opont, chairman of the Provisional Electoral Council (CEP), said yesterday that the vote had been pushed back because of "obvious security concerns."
Opont complained that CEP personnel had been attacked and that several polling stations had been burned overnight.
The poorest country in the Americas had been due to go to the polls to elect a successor to President Michel Martelly and seek a way out of a deep political crisis.
But opposition activists fear the poll will be rigged in favor of Martelly's hand-picked successor, Jovenel Moise, and their champion Jude Celestin is boycotting the vote.
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The decision will be seen as a blow to the ambitions of the United States, Haiti's key foreign partner, which had pushed for voting to go ahead despite the violence.
Martelly, who has denounced protest and accused critics of trying to destabilize Haiti, was due to broadcast an address to the nation later in the day.
The former popular singer is barred from seeking re-election and has vowed to hand over power to a successor on February 7 in accordance with the constitution.
But many polling stations remained closed due to unrest or electoral skullduggery and voter turnout was tiny.
Celestin's supporters cried foul, accusing Martelly of mounting an "electoral coup d'etat."
The government allowed a hastily assembled independent commission to review the ballots, but the opposition has not been mollified and protests have erupted.
"On the 24th, it's 'No'," Celestin told AFP this week. "I won't take part in this farce, it will be a selection not an election because there will only be one candidate."
They blocked several downtown streets and fought running battles with police.
This week, an umbrella body of poll observers declared they would not take part in an event "that the CEP wants to pass off as an election."
On Tuesday, observers from the Organization of American States, expressed "concern on the current political impasse ahead of tomorrow's second round of elections.