Another aftershock hit the Haitian capital Thursday night, sending some earthquake survivors into the streets in the dark.

People in Port-au-Prince said the brief temblor was not as strong as several others since the magnitude-7.0 earthquake that devastated the city Jan. 12. Ensuing aftershocks have reached as high as magnitude-5.9.

The U.S. Geological Survey did not immediately have a measurement of the aftershock. Geophysicist Susan Potter said people can feel aftershocks that register as little as magnitude-2.0, but the service has yet to detect anything weaker than a magnitude-4.5 trembler in Haiti, where detection equipment is not densely concentrated.

Earlier Thursday, the United Nations said it will establish a "cash for work" program in Haiti to help the country recover from quake and UN Secretary General Ban Ki-moon called on the international community for its support.

"We now have to move from the emergency response to face ongoing relief and eventually construction of the Haitian economy," Ban said at a news conference in New York with Bill Clinton, the UN special envoy and former U.S. president.

United Nations Secretary General Ban Ki-moon, right, and former U.S. president Bill Clinton speak to reporters at the United Nations in New York on Thursday. (Mary Altaffer/Associated Press)

"During my recent visit to Haiti I have met many people," said Ban, referring to a one-day visit on Jan. 17. "What they ask us is that they need the water, food, the shelter and all these basic needs.

"They need a better future and permanent jobs, to work with dignity."

The proposed cash-for-work program would employ young Haitian men and women to help with clearing streets of debris and the demolition of crumbled buildings.

Clinton will lead the program, for which the United Nations Development Program has already requested $41 million US from the world community.

"It is really important to give the young people something positive to do and a lot of people there want to rebuild the country," Clinton said.

He listed new airports, new ports and the rebuilding of Port-au-Prince as key projects, ones that could be included in Haiti's pre-existing development strategy.

Humanitarian aid remains top priority

But the work program is the last of three priorities set out by Ban on Thursday.

Providing humanitarian assistance continues to be the top priority, followed by providing security and stability to the Haitian people.

At least two million people are homeless in Haiti — 500,000 more than originally estimated — and officials fear an outbreak of disease among earthquake survivors living in makeshift camps.

"The next health risk could include outbreaks of diarrhea, respiratory tract infections and other diseases among hundreds of thousands of Haitians living in overcrowded camps with poor or non-existent sanitation," Dr. Greg Elder, deputy operations manager for Doctors Without Borders in Haiti, told The Associated Press.

Fritz Longchamp, the chief of staff to President Réne Préval, told The Associated Press that the government will resettle 400,000 survivors from the stricken capital in temporary camps outside town. Buses will start moving people from the capital in a week to 10 days, Longchamp said.

Medical clinics have 12-day patient backlogs, which means untreated injuries are festering.

Medical workers struggled to care for the victims even as a pair of aftershocks rattled the Haitian capital, Port-au-Prince, on Thursday. The U.S. Geological Survey said one tremor at 11:45 a.m. ET had a preliminary magnitude of 4.9.

Port destroyed

One of the main obstacles to the delivery of much-needed aid is the condition of Haiti's main port. Experts said the earthquake-inflicted damage may take years to repair. The pavement where containers are transferred from ships was torn to pieces.

The cranes used to unload ships are now damaged, some were tossed into the water by the force of the quake.

The U.S. marines have been called in to help unload humanitarian aid on the last standing jetty. Normally the port would be humming with the sound of loaders and cranes but Thursday just before noon the first shipping container since the quake filled with vegetable oil and wheat was placed on a truck.

Reginald Villard is a shipping agent overseeing the loading. He admits things are working slowly.

"Right behind me you can see the first humanitarian aid that arrived last Sunday, he said. "That means food and other supplies has been sitting in the containers on the pavement baking in the sun for four days."

Medical attention is desperately needed in Port-au-Prince, where patients must wait for days for help, and doctors often operate without anaesthetics. (Reuters)

The aftershocks sent rescue crews scrambling from the ruins of buildings where they were searching for survivors. They also sent residents out into the streets again. Since the Jan. 12 quake that ruined much of Port-au-Prince, about 50 aftershocks of magnitude 4.5 or higher have hit the area.

Airports remain backed up

Adding to the problems of finding shelter for survivors is the backlog at Toussaint L'Ouverture International Airport in Port-au-Prince. U.S. Gen. Douglas Fraser, who is head of the U.S. Southern Command that is running Haiti's airports, said there is a waiting list of 1,400 flights to get in, but the airport can only handle 120 to 140 flights per day.

Fraser said additional landing zones in Dominican Republic and in Jacmel, in southern Haiti, have been opened up to take some of the load.

Speaking to reporters at the Canadian Embassy, Haitian Prime Minister Jean-Max Bellerive said the relief effort has struggled with issues of logistics, a lack of places to store relief supplies and a shortage of gasoline. Haitian Prime Minister Jean-Max Bellerive tells reporters at the Canadian Embassy on Thursday that the relief effort has struggled with logistical problems, inadequate storage for supplies and a lack of fuel. (CBC)

He also said displaced people have set up about 229 spontaneous camps in the area.

"So the distribution [of aid] is very difficult," Bellerive said.

Building collapses feared

According to the European Commission, many of the two million homeless are afraid to stay in their homes, fearing the buildings will topple in aftershocks.

The commission also believes that 250,000 are in need of urgent aid. While the death toll is estimated at 200,000, some say an exact tally will never be known.

“I don’t think we will ever know what the death toll is from this earthquake,” Edmond Mulet, the newly appointed head of United Nations operations in Haiti, told the New York Times.

He said people are burying bodies by themselves, many have been thrown into dumps outside the city and an untold number still lie under the rubble.

About 80,000 are believed to have been buried in mass graves. Workers have been using earth-movers to carve out mass graves in Titanyen, north of Port-au-Prince, to bury 10,000 victims in a single day.

About 100 surgeons, nurses and medics with the 1st Canadian Field Hospital will deploy to Haiti beginning this weekend, CBC News has confirmed.

The mission will be based in Jacmel, a city of 80,000 near the capital, which has an airstrip already in use by the Canadian military. The unit will set up a hospital with an intensive-care unit and up to 50 beds.

Two surgical teams, including a general surgeon and an orthopedic surgeon, will be in charge.

With files from The Associated Press