Duvalier said he was prepared to face "persecution." [AFP]

Rene Preval, the Haitian president, has said that ex-dictator Jean-Claude "Baby Doc" Duvalier had every right to return home from exile, but must now face an investigation of alleged abuses during his reign.

Preval's first public comment on Duvalier since the former strongman's astonishing arrival in Haiti a week ago came at a news conference on Saturday during a surprise trip of his own to the neighbouring Dominican Republic.

"Duvalier had the right to return to the country, but under the constitution, he also must face justice," Preval told reporters.

"If Duvalier is not in prison now, it is because he has not yet been tried."

Accompanied by prime minister Jean-Max Bellerive, Preval said they met with Leonel Fernandez, the Dominican president to discuss Haiti's political crisis and a cholera epidemic.

Preval added that by law, Haitians cannot be barred from their homeland, and that applies to both Duvalier and former president Jean-Bertrand Aristide, who has been in exile in South Africa since his ouster in 2004 but recently spoke of wanting to come back.

"They do not depend on my decision," Preval said. "It is the nation's constitution that prohibits (forced) exile."

Preval declined to say whether he knew ahead of time about Duvalier's sudden appearance in the country on January 16, after 25 years in exile.

Duvalier says he came to help his shattered nation rebuild from last year's massive earthquake, which killed an estimated 316,000 people.

Duvalier said he was prepared to face "persecution."

However the former leader, who ruled Haiti from 1971 to 1986 through terror and the regime he inherited from his father, has found himself under investigation for corruption, embezzlement, torture, arbitrary imprisonment, crimes against humanity and other alleged abuses during his reign.