President Preval made the pledge Friday in the city of Gonaives in a speech marking Haiti's Independence Day.
The first round of voting is scheduled for February 28.
Haiti's electoral council has banned the political party, Fanmi Lavalas, of former President Jean-Bertrand Aristide from taking part in the vote, saying it submitted improper documents. The decision has drawn criticism from the former president, who was overthrown in a 2004 rebellion and is living in exile in South Africa.
The Fanmi Lavalas party - which is widely backed by Haiti's poor - has been barred from previous elections over other alleged failures to meet legal requirements.
The presidentially appointed electoral council also has disqualified more than a dozen political groups from the process.
Also Friday, Mr. Preval said he would use his last year of his five-year presidential term to boost agriculture and improve roads. The annual address in the city of Gonaives marked Haiti's independence from France on January 1, 1804, after a slave revolt.
Earlier this week, U.S. Secretary of State Hillary Clinton issued a statement congratulating the people of Haiti as they celebrate the 206th anniversary of the country's independence.
Secretary Clinton also saluted the many contributions Haitian-Americans have made to the culture and prosperity of the United States.