Haiti's president and UN representatives are calling for calm after a string of riots related to a cholera outbreak that has killed more than 1,000 people.

A girl with cholera symptoms receives treatment at the Doctors Without Borders temporary hospital in Port-au-Prince last Friday. (Emilio Morenatti/Associated Press)

The government sent top officials to the north Tuesday in hopes of quelling the unrest, which began amid rumours that Nepalese peacekeepers were responsible for the outbreak — a rumour the United Nations has denied.

Haiti's police chief, the health minister and other cabinet officials headed to Cap-Haitien, the country's second-largest city, where protesters erected barricades of flaming tires and other debris, and clashed with UN troops.

President René Préval said barricades and protests were keeping people from getting the care they needed.

"Gunshots, throwing bottles, barricades of burning tires will not help us eradicate cholera bacteria," he said Tuesday. "On the contrary, it will prevent the sick from receiving care and to deliver medicine where it is needed."

The UN office for the co-ordination of humanitarian affairs said the violence has slowed the delivery of cholera prevention and treatment supplies. The United Nations has cancelled several aid flights and a number of relief organizations have also scaled back their activity in the region, the humanitarian agency said.

Préval also admonished protesters, saying looting would not help stem the epidemic.

1st case in Dominican Republic

Meanwhile, officials in neighbouring Dominican Republic said Tuesday that the first case of cholera had been detected in the country.

Public Health Minister Bautista Rojas said a Haitian worker who lives in the Dominican Republic had a confirmed case of cholera.

Haiti's Ministry of Public Health said 1,034 people have died from cholera and 16,799 people have been hospitalized.

But Doctors Without Borders, an emergency medical relief organization, said it has treated 16,500 people with suspected cholera symptoms since late October.

"Both the short-term and long-term forecasts indicate that this situation will get worse, possibly far worse, before it gets better," said Stefano Zannini, head of the Doctors Without Borders mission in Haiti.

Dr. Jon Kim Andrus, deputy director of the Pan American Health Organization, said Tuesday that officials expect the disease will spread to new areas as the number of cases increases.

He said cholera continued to spread through six of the country's 10 departments, or administrative regions, over the weekend: Artibonite, Central, Northwest, North, South and West.

He said six communities in Port-au-Prince reported an increase in cholera cases, including Cité Soleil, a crowded slum.

"The rise in the number of cases in Cité Soleil is particularly worrisome to us, because we know the conditions of poverty, including the very crowded living conditions, poor sanitation and lack of access to potable water."

He said health officials are working to track the spread of the disease and identify hot spots where cases are multiplying rapidly.

The outbreak that began last month has brought increased misery to the entire country, still struggling with the aftermath of January's devastating earthquake.

But anger has been particularly acute in the north, where the infection is newer, health care sparse and people have died at more than twice the rate of the central region where the outbreak was first noticed.

With files from The Associated Press