Bill Clinton: Aid Agencies Need U.S. Cash for Haiti Quake Relief

Former President Bill Clinton today called on Americans to open their pocketbooks and donate more cash to the ongoing earthquake relief effort in Haiti.

"We've got to have more," Clinton said on "Good Morning America." "We need more food, water, medical supplies and shelter materials in quickly."

Clinton, also the United Nations special envoy to Haiti, acknowledged that some Americans may be eager to travel to the country to help with the recovery and rebuilding, but, he said, such opportunities will would come later.

VIDEO: Former Presidents Clinton and George W. Bush help coordinate recovery efforts.Play

"Logistically, it's better if people just even have a little money to go ahead and give cash now," he said.

Crowding at the single-runway, Port-au-Prince airport has limited the number of flights that can land on the island at a given time and, once on the ground, huge cargo planes that take hours to unload are piling up on the tarmac.

"Yes, we will have bottlenecks," Clinton said. But, he said, the primary focus remains a search-and-rescue effort.

VIDEO: U.S. Government and Aid Groups Rush Support to HaitiPlay

"We have about another week to dig through the rubble and clear out the basic structure of the streets. And, then, we've got to go through the recovery and rebuilding process."

The process will likely require hundreds of millions of dollars in foreign aid, something that Clinton has experience coordinating in his role with the Clinton Foundation and when he and former President George H.W. Bush collaborated to raise funds for victims of the 2004 Southeast Asian tsunami.

The White House Thursday formally called on Clinton and former president George W. Bush to coordinate U.S. fundraising efforts.

VIDEO: Bill Clinton weighs in on Afghanistan, health care reform and race.Play

"The president believed that the partnership that President George W. Bush created between his dad and former President Clinton was obviously a highly effective way of ensuring that after this ... search-and-rescue phase of this operation ... concludes, obviously there is still going to be a tremendous need -- and there will probably be a tremendous need for many, many months to come -- that that's the best vehicle and the most effective vehicle for setting that up," White House Press Secretary Robert Gibbs said.

Clinton, Bush to Lead Haiti Relief Fundraising Effort

Former Presidents Clinton and Bush issued a statement accepting President Obama's request to lead private-sector fundraising efforts, saying, "In the days and weeks ahead, we will draw attention to the many ways American citizens and businesses can help meet the urgent needs of the Haitian people."

ABC News video of Bill Clinton meeting Kim Jung Il.Play

After the Southeast Asian tsunami, the United States gave more than $1 billion in private aid with the average donation being $56, Clinton said. In the first 48 hours after the quake struck, the American Red Cross says it has raised more than $35 million for Haiti so far.

The larger goal is to raise as much money as possible and to put it into the most constructive channels as possible," Clinton said on "GMA."

Responding to some conservatives' criticism of U.S. aid flowing to Haiti, Clinton said, "We give some money to Haiti every year, not very much. ... When people get in trouble, Americans are the most generous people in the world."

VIDEO: Bill Clinton speaks out on the obesity crisis in America.Play

Clinton has focused much of his post-presidency humanitarian work on Haiti, visiting the country several times since leaving office in 2000.

The Clinton Foundation works in Haiti on a number of issues, including health care, AIDS, the environment and economic development.

Clinton, who is popular among many Haitians for using the threat of U.S. force to oust a dictatorship in 1994, visited Haiti as president in 1995.

In an interview on "World News" Wednesday, Clinton said he thought the disaster in Haiti, affecting more than 3 million people, may be one of the most devastating tragedies ever to hit the United Nations.

VIDEO: Earthquake victims wait for aid in the streets of Port-au-Prince.Play

"Our U.N. hotel, as you know, [was] five stories [and] completely collapsed." Clinton said.

At least 16 U.N. employees, including the chief of the U.N. mission in Haiti, Hedi Annabi, have died, with at least 56 more injured, a U.N. spokesman said. Nearly 100 more are unaccounted for.

"It's highly likely to be the highest mortality count we've ever had," Clinton said.

Officials speculate that up to 50,000 people may have died across the island.

To learn more about ways that you can help the victims of Haiti's earthquake, click HERE.

ABC News' Yunji de Nies and Kristina Wong contributed to this story.