Aid is beginning to reach storm survivors, but thousands of people remain stranded after roads flooded and bridges collapsed.
A ship carrying about 33 tons of food, water and other relief supplies docked in Gonaives and UN peacekeepers are distributing the aid to those in need.
"The objective is to get this [aid] as soon as possible to the population, who have gone without food or water for about five days," Teresa Bo, Al Jazeera's correspondent in Port-au-Prince, Haiti's capital, said.
Earlier on Friday, Haiti's civil protection office said that at least 136 people had died as a result of the storm, mainly in Gonaives.
Large areas of Gonaives are still under water and up to 70 per cent of its 300,000 residents have been without water or food since the storm hit on Monday, she said.
About 10,000 of the city's residents have been driven into shelters because of the flooding, Alta Jean-Baptiste said.
Other areas of Haiti affected by the storm remain inaccessible by road, hampering relief efforts.
An emergency official said: "Several southern towns have also been flooded and access is impossible because the roads were cut off and the bridges collapsed,"
Many people are scouring the streets in an effort to find food, Bo reported.
"Most of the roads are completely blocked and the weather has not been helping in order to deliver aid by air, so the situation is very complicated on the ground," she reported.
The UN is in the process of launching an international appeal after Haiti requested international assistance, a spokesperson for the Office for the
Co-ordination of Humanitarian Affairs (OCHA), said.
The European Commission on Friday has also launched its own aid action for Haiti.
"The European Commission has today launched a fast-track funding decision for two million euros ($2.9m) to provide relief for victims of Tropical Storm Hanna in Haiti," the EU's said in a statement.
Daniel Rouzier, the Haiti chairman of Food for the Poor, said that the situation in the country is "catastrophic".
"We, just like the rest of the victims ... have limited mobility. You can't float a boat, drive a truck or fly anything to the victims," he said.
Areas of northern Haiti are without power due to landslides and flooding after Hanna rained heavily over the mountainous region for four days.
Government and UN convoys attempting to deliver food have been "attacked by famished people," an official said.
Myrta Kaulard, a UN food agency representative, said: "All roads able to access Gonaives are cut either by bridges that have collapsed, by trees that have fallen down, or by waters that have washed away parts of the streets."
Helicopters from the UN peacekeeping mission in Haiti have rescued survivors from rooftops in Gonaives.
|Large areas of the city of Gonaives are under water after the storm [AFP]
UN officials say they are also seeking ways for the helicopters to deliver food, water and water purification tablets.
"I don't know how much longer we will remain alive," Germain Michelet, a priest who took refuge from the flooding on the second floor of the archbishop's office, said.
"If we are forced to go through another night under these conditions, there will not be many survivors."
A category four storm, Ike, is also set to shave northern Hispaniola – the island shared by Haiti and the Dominican Republic – on Saturday.
"What we do know is that most of the residents, especially of Gonaives, are leaving," Bo said.
"It is not clear yet whether they are being evacuated, but humanitarian organisations are trying to get people out of there.
The disaster comes days after hurricane Gustav and tropical storm Fay swept Haiti, killing 117 people across the country.