An official announcement is expected from U.N. Secretary-General Ban Ki-Moon on Tuesday, Clinton spokesman Matt McKenna said.
U.N. peacekeepers have provided the only real security in Haiti since 2004, and are helping training the country's under-equipped national police force to retake control eventually. But protesters and some Haitian lawmakers denounce the international troops as an occupation force and have called for them to leave.
Clinton himself is popular among many of Haiti's poor, however, for using the threat of military force to oust a dictatorship in 1994. U.S. Army troops and Marines then quickly arrived to pave the way for the return of elected President Jean-Bertrand Aristide, who had been deposed in a coup.
Aristide was later ousted again in a 2004 rebellion and flown into exile aboard a U.S. plane. Some Haitians still hope for his return.
"For the U.N., for Haiti, and for former President Clinton, the appointment is a popular choice, because Clinton is loved in Haiti as well as with Haitian-Americans because of his support, during his presidency, for legislation which provided immigration benefits and relief from deportation to certain Haitian nationals," said CBS Foreign Affairs Analyst Pamela Falk reporting from the U.N. "And when Clinton went to Haiti in March with the Secretary General, Ban Ki-moon and Haitian-American singer Wyclef Jean, he was received as a hero."
Clinton toured the Haitian capital of Port-au-Prince with the U.N. chief to encourage investment after a year that saw a food crisis, destabilizing riots and four devastating tropical storms.
"Because of his history with Haiti, former President Clinton will bring visibility, and probably much needed economic assistance to Haiti," Falk added.
The following month, he attended a donors conference in Washington that resulted in pledges of $324 million for the struggling country. Haiti is the hemisphere's poorest nation and been mired for decades in political and social turmoil.
Because of his marriage to U.S. Secretary of State Hillary Rodham Clinton, State Department lawyers must approve and review some of Clinton's international activities under an agreement between the U.S. Senate and the Clinton Foundation, which works in Haiti on a number of issues including health care, AIDS, the environment and economic development.
Officials said the State Department is aware of the appointment but could not immediately say if its lawyers have signed off on it. U.N. officials did not immediately comment.
Haiti does not currently have a special U.N. envoy, and it is not clear what Clinton's duties will be. The Miami Herald, which first reported the appointment, said he will be expected to visit the Caribbean country - a two-hour flight from Miami - at least four times a year.
Clinton visited Haiti as president in 1995 and again in 2003. Hillary Rodham Clinton has also visited several times, most recently for an April meeting with President Rene Preval en route to the Summit of the Americas in Trinidad.