The United Nations has a "moral responsibility" to help impoverished Haiti end a devastating cholera outbreak some blame on peacekeepers, Secretary-General Ban Ki-moon says.

Ban spoke to The Miami Herald ahead of a visit to the Caribbean nation due to begin Monday during which he is set to visit families affected by cholera. The United Nations has so far denied any responsibility over the outbreak that has killed more than 8,000 people and infected more than 700,000.

There had been no cholera in Haiti for at least 150 years until it was allegedly introduced by Nepalese UN peacekeepers sent there in the wake of the devastating January 2010 earthquake.

The source of the cholera epidemic was traced to a river that runs next to a UN camp in the central town of Mirebalais, where Nepalese troops had been based.

The strain of cholera is the same as one endemic in Nepal.

"Regardless of what the legal implication may be, as the secretary-general of the United Nations and as a person, I feel very sad," Ban told the Herald.

"I believe that the international community, including the United Nations, has a moral responsibility to help the Haitian people stem the further spread of this cholera epidemic."

The United Nations has so far failed to offer an apology or compensation for the outbreak, even as three different lawsuits have been filed in US courts.

"The diplomatic difficulties surrounding this issue must be overcome to ensure the Haitian people that the epidemic can be stopped in the shortest possible time frame and pay full compensation for the damages suffered," the UN's human rights expert on Haiti Gustavo Gallon said.

During his visit, Ban plans to focus on getting donors to contribute to a $2.2 billion, 10-year cholera elimination campaign because Haitians have "suffered a lot" from the epidemic.

He said Haiti must address the root causes of cholera -- poor sanitation -- to prevent another epidemic.

"The international community has been struggling to overcome this global financial difficulty, and we have so many crises happening at the same time around the world," said Ban. "That is one reason why we have not been able to effectively mobilize."

In Haiti, Ban will travel to the Centre Department to launch a "total sanitation campaign" with Prime Minister Laurent Lamothe, in an effort to improve sanitation and hygiene in rural areas.

Ban will then meet with President Michel Martelly and lawmakers in the capital Port-au-Prince, as well as meet with leaders from the UN mission MINUSTAH, according to the UN chief's office.

- 'Crucially important' vote -

Haiti is also wrestling with deep political instability after the earthquake that killed between 200,000 and 250,000 people and displaced another 1.5 million from their homes in one of the world's poorest countries.

Legislative elections have been delayed for three years as the country struggles to get back on its feet.

The long wait has triggered a political crisis marked by anti-government street rallies.

"My political message to Haitian leaders, government and parliamentary leaders, will be that it's crucially important that this election be held as agreed and scheduled in October," Ban said.

Following his stay in the country, Ban will then head to the Dominican Republic, which shares the island of Hispaniola with Haiti.

There, Ban will meet with President Danilo Medina, meet leading lawmakers and address a joint session of Congress.