Almost 500 bodies have been found in the port city of Gonaives after floodwaters caused by recent storms receded, according to reports.
Commissioner Ernst Dorfeuille told Reuters news agency 495 bodies had been found and the toll get higher.
A ship carrying 33 tons of UN aid arrived in Haiti on Friday to help an estimated 600,000 people struggling in the wake of tropical storm Hanna.
The storm is heading for the US, while Hurricane Ike threatens the Bahamas.
The US National Hurricane Center says Ike is a Category Three hurricane, with winds of up to 185 km/h (115mph).
It is expected to pass near or over the Turks and Caicios Islands and south-eastern Bahamas late on Saturday or early Sunday – by which time it could be a major hurricane, forecasters say.
Tropical storm Hanna is causing heavy squalls off the coasts of North and South Carolina and tropical storm warnings are in force along the Atlantic coats from Georgia to New Jersey.