"I saw a city mostly submerged in deep mud (and) people still stranded on roof tops. Other people are still living in school and in a church," Farrow told AFP after a tour of storm-ravaged Gonaives in the northern part of the country.
"There is a sense of confusion, loss and anger. The people in the shelters had not eaten for days, (there is) not enough water coming -- of course there is in no sanitation of any kind," she said.
Farrow said she would spread word of the devastation upon her return to the United States on Monday.
"My hope is to be a good steward of this information, to take this message to the United States and the international community with the hope that the conscience of the world will respond," she said.
The World Health Organization has said that 800,000 people have been affected by the four major storms that tore across the country in recent weeks.