The U.N. and the U.S. State Department on Wednesday are running the largest global fundraiser to date, asking nations to pony-up almost $4 billion to rebuild Haiti in the wake of the devastating January earthquake.

The objective of the organizers is to garner commitments for $1.3 billion in the next year, half of which they want up front to meet immediate needs.

Haiti announced ahead of the conference that former President Bill Clinton would serve as co-chair of a new commission overseeing the huge aid effort, alongside the impoverished nation's Prime Minister, Jean-Max Bellerive.

Clinton's wife, U.S. Secretary of State Hillary Rodham Clinton will also be at the aid drive - as a reminder of the power couple who are hailed in Haiti for their devotion when Bill Clinton was president.

The idea is to put Haiti back on center stage. U.N. staff and workers from non-government organizations have complained that the campaign to raise $1.5 billion remains 50 percent short, and that initial public attention has waned.

"The appeal has stagnated," a spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs, Elisabeth Byrs, said in Geneva a day before the Donors Conference.

The new commission headed by Clinton and Bellerive is part of the plan for aid and rebuilding that Haitian officials are carrying to the conference at U.N. headquarters.

Read More: CBS News