Hurricane Matthew has left more than 100 people killed, according to the interior ministry on Thursday.
Reuters has also reported 28 more deaths, quoting local officials, bringing the total up to 136.
However, this number is expected to rise as rescue teams reach badly hit areas.
The strongest hurricane in the Caribbean for years swept through the poverty-stricken country on Tuesday, with winds reaching up to 230 km/h, flooding towns, downing power lines and cutting people off from accessing food and money.
The Miami Herald reported that Interim President Jocelerme Privert said on Thursday that "the situation is catastrophic."
"There are a lot of areas in the country that have been affected, a lot of places that are difficult to access."
The country's civil protection bureau had confirmed 38 dead in the department of Grand'Anse, 34 in Ouest, 26 in Sud, three in Artibonite, three in Nippes, three in Sud-Est and one in Nord-Ouest.
The situation in the towns of Jeremie, Les Cayes, Port-Salut, Petite-Riviere de Nippes and Dame Marie is considered to be particularly critical.
According to CARE Haiti, 80 percent of the buildings in the town of Jeremie were destroyed.
Mercy Corps, a humanitarian NGO, stated that 80 percent of banana crops in the region of Arcahaie were wiped out, leaving around 20,000 families without their livelihoods.
On Thursday, rescue teams and aid began arriving from around the world as the scale of the devastation left in the hurricane's wake became clear.
USAID, the American international development agency, announced it would provide 1.5 million US dollars in immediate aid on Thursday, while one of its disaster assistance response teams is already on the ground.
A report from the UN's Office for the Co-ordination of Humanitarian Affairs (OCHA) on Wednesday estimated that at least 350,000 people are in need of assistance.
Hurricane Matthew was still a Category 4 storm on Thursday as it approached the coast of Florida. Millions of people are being evacuated in the US as the storm may hit Florida, Georgia and South Carolina as it moves up the Atlantic coast.