Aid is getting through but distribution is a problem
Haiti's new prime minister, Michele Pierre-Louis, says people displaced and stranded by recent storms are in urgent need of food and water.
She said Haiti had suffered ecological and economic disaster in the wake of four successive storms that left more than 550 people dead.
Strong winds and torrential rains over the past month have battered Haiti's already fragile infrastructure.
The UN and other agencies now say they face a huge task in distributing aid.
Ms Pierre-Louis told the BBC's Caribbean Service that the priority was to get supplies to people cut off by widespread flooding.
She said that since early on Tuesday morning - when weather conditions had improved - helicopters had been flying supplies from a US aid ship to people stranded throughout the country.
"This is the most urgent part. Then we are making an assessment of the destruction, in terms of education, health and agriculture, so that we can launch an urgent plea to the international community for help," Ms Pierre-Louis said.
The prime minister only took office on 5 September after a tortuous confirmation process, with her government replacing the one dismissed in April for failing to manage the economy of the desperately poor country.
That came against a background of riots over high food and fuel prices, during which at least six people were killed.
RECENT MAJOR STORMS
Hurricane Ike: September
Tropical Storm Hanna: September
Hurricane Gustav: August, September
Tropical Storm Fay: August
Ms Pierre-Louis said her government would try its best to deal with the situation but admitted that Haiti, beset by years of political instability, had very weak institutions.
She said she was reaching out to the country's parliament, political class and the private sector.
"I think it is time to put behind us all our frustrations and differences, and if we're not able to do that, believe me, I don't think we're going to get out of this."
The last hurricane to affect Haiti, Ike, compounded the devastation wrought by Tropical Storm Fay, Hurricane Gustav and Tropical Storm Hanna.
The northern city of Gonaives has been particularly badly hit by flooding. So far 101 bodies have been found there as the floodwaters recede.
Vicky Delore-Ndjeuga, a spokesman for the UN Mission in Haiti, said that number could increase as people become increasingly desperate for aid.
"If we don't find a way to deliver massive humanitarian aid, [we] will see fights and riots that will kill more people than the cyclone did," she told the AFP news agency.
Elsewhere in the region, in the Turks and Caicos Islands and the southern Bahamas, people are also facing huge repairs after Ike roared through the region as a powerful category four hurricane.
In the Turks and Caicos, nearly 80% of buildings are reported to have been damaged.