Police in the flooded Haitian city of Gonaives say at least 495 bodies had been found on Friday as muddy floodwaters following tropical storm Hanna began to recede.
"The weather is calm now and we are discovering more bodies. We have found 495 bodies so far and there are 13 people missing," said commissioner Ernst Dorfeuille.
Food and relief supplies have begun arriving in Gonaives.
The 495 dead in Gonaives brought the toll for all of Haiti to at least 529 after a week of floods and mudslides.
A freighter with food supplied by the UN's World Food Program and carrying other supplies such as drinking water docked in the port city, where the streets were thick with mud and littered with the carcasses of animals after four days of floods.
The United Nations is launching an appeal for emergency funds to help up to 600,000 Haitians while the International Federation of Red Cross and Red Crescent Societies appealed for $US3.4 million in donations.
UN humanitarian affairs chief John Holmes said 250,000 people had been "badly affected" in Gonaives alone, with some 70,000 still in shelters.
Haiti, the poorest country in the Americas where most people scrape by on less than $US2 a day, has been hit by three successive storms in less than a month.
Tropical Storm Fay killed more than 50 people last month while Hurricane Gustav left at least 75 people dead.
Tropical Storm Hanna this week sent up to 2m of muddy water pouring through Gonaives.
The storms have flooded fields and compounded the misery of a population of about nine million struggling to cope with rising food and fuel prices.
Hanna had pulled away from Haiti on Friday and was set to crash ashore on the US East Coast in the Carolinas early on Saturday.
In its wake, however, came fierce Hurricane Ike, which could dip close to northern Haiti before taking aim at south Florida, Cuba or potentially the Gulf of Mexico next week.
Haiti, where more than 70% of the population live in poverty, is especially prone to flash-flooding and mudslides. Haitians have cut down most trees and bushes to make cooking fires, which causes erosion and worsens flooding.
The airport in the capital Port-au-Prince reopened on 3 September, allowing a group of UN experts to evaluate the extent of the damage.