UN spokeswoman Elisabeth Byrs said that unless funds were provided, “all our efforts can be outrun by the epidemic”.
She said the disease had so far infected at least 11,125 people in five of Haiti’s 10 districts.
Aid agencies are battling to contain cholera in the capital Port-au-Prince, amid fears it will spread through camps housing 1.1m earthquake survivors.
More than 80 people have died in the past 24 hours across the country, according to the health ministry.
High fatality rate
Ms Byrs, of the UN’s Office for the Co-ordination of Humanitarian Affairs (OCHA), said the funds will be used to bring in more doctors, medicines and water-purification equipment.
“We absolutely need this money as soon as possible,” she said.
Stefano Zannini, head of mission for Medecins Sans Frontieres in Haiti, said on Friday that hospitals in Port-au-Prince are overflowing and patients may have to be treated in the streets.
“We are really worried about space,” he said.
“If the number of cases continues to increase at the same rate, then we are going to have to adopt some drastic measures. We are going to have to use public spaces and even streets. I can easily see this situation deteriorating to the point where patients are lying in the street, waiting for treatment. At the moment, we just don’t have that many options.”
The World Health Organization said on Friday it did not expect the epidemic to end soon.
“The projections of 200,000 cases over the next six to 12 months shows the amplitude of what could be expected,” said spokesman Gregory Hartl.
He said that the current fatality rate of 6.5% was far higher than it should be.
“No-one alive in Haiti has experienced cholera before, so it is a population which is very susceptible to the bacteria,” he said. “Once it is in water systems it transmits very easily.”
The outbreak began in Haiti’s Artibonite River valley in mid-October and at first seemed to have been contained.
But Hurricane Tomas, which struck earlier this month, flooded rivers believed to be contaminated with cholera and submerged refugee communities already struggling to survive.
The disease is spread by contaminated drinking water or food, but is treatable with oral or intravenous rehydration and antibiotics.
Aid agencies say access to clean water is a major problem, and they are struggling to get the message across to Haitians to seek medical help as soon as cholera-like symptoms appear.
Even before the earthquake only 40% of Haitians had safe drinking water.
Haiti’s besieged health services have been warned to expect a different scale of disaster if cholera takes hold in the capital, which was devastated by January’s earthquake that left more than 250,000 people dead.
“We greatly fear a flare-up in the capital which would be serious given the conditions in the camps,” Claude Surena, president of the Haitian Medical Association, told AFP news agency.
Meanwhile, the first portion of US financial aid for reconstruction in Haiti is on its way, more than seven months after it was promised to help the country re-build after the earthquake in January.
The $120m (£74m) – about a tenth of the amount pledged in total by the US – has faced several delays.
Only 37.8% of the money pledged by all countries for 2010-11 has been delivered to the poverty-stricken nation.
I have seen the past – I know tomorrow.
The situation mirrors one in which the first visitors to the Americas spread disease among the native population, killing millions. Haiti’s original Indian population was decimated by disease.
Now we have the United Nations bringing death to the people of Haiti.
Before sending troops to any area, there should be a medical check to make sure none of the UN people carries disease strains unknown in the country of occupation. Haiti was cholera free. Now it faces a massive and sweeping epidemic that will effectively pollute the nation for at least 50 years – assuming that effective corrective steps can be taken.
The very nature of Haiti’s present situation, and expected situation makes this timeline much shorter than reality. In other words, the stupidity of the UN has effectively destroyed Haiti – yet again.
MINUSTAH has really been of no use to Haiti.
It has made the Haitians dependent upon outsiders for law and order.
When the earthquake struck MINUSTAH disappeared for more than a week. When it finally surfaced, MINUSTAH spokesmen said they had remained hands off so as not to interfere with the running of Haiti. Check back and see exactly what was said.
Now, the MINUSTAH’s Nepalese battalion has polluted much of Haiti’s water supply.
When one sees what actually happened a cynic must suspect that the Cholera infection was a coldy calculated effort to derail the elections and tighten MINUSTAH’s hold on Haiti.
The only goal of the UN/MINUSTAH in Haiti, as in the Congo, is prolongation of its stay. Haiti is worth billions of dollars to the United Nations and to Hell with the Haitian people.
Unfortunately, President Preval is a key player is this national disaster.
He must face justice.
There should be no immunity for Preval and his team of criminals.