Heavy rains expected in Haiti will delay the building of big refugee camps outside the capital Port-au-Prince, relief officials said Thursday. (Associated Press)

Relief officials in Haiti have delayed plans to build big refugee camps outside the capital Port-au-Prince with forecasters warning of the country's first big rainstorm since the earthquake.

Instead, they are telling the homeless to pack up their tents and tarps and return to destroyed neighbourhoods.

People who lined up at a downtown site Thursday to register for the new campaign to resettle more than 1.2 million Haitians expressed skepticism and were dismissive of the plan, and relief officials acknowledged its immense challenges.

The rainy season is less than a month away, and forecasters say Haiti's first big storms since the Jan. 12 quake could arrive by this weekend. Many dwellings are severely damaged or clinging to the sides of hillsides, vulnerable to mudslides if heavy rain comes.

"There will be flooding," a top UN official for Haiti, Anthony Banbury, told a New York news conference this week. "There will be discomfort, misery. And that's not avoidable."

Gerald-Emile Brun, an architect with the Haitian government's reconstruction committee, agreed.

"Everything has to be done before the start of the rainy season, and we will not be able to do it," he said Thursday.

Brun suggested that Haitians, who expect little of their corrupt and inefficient government, may largely be left to sort it out themselves.