Bernard Kouchner, also a former French health minister, told Europe-1 radio on Monday that hundreds had been "chased" from northern Morocco near Melilla, a Spanish enclave that has been the scene of attempts by huge groups of Africans to get into Europe.
Kouchner said Morocco had abandoned at least 400 sub-Saharan Africans caught near Melilla, leaving them stranded with "nothing to eat".
"It makes you sick to think that ... people are dying at this moment looking for water in the desert," Kouchner said.
"Doctors Without Borders has seen them," he said of the group also known as Medecins Sans Frontieres (MSF).
Kouchner also criticised the response of the European Union to the situation as outmoded.
"To close the door does nothing. They go through the window. They break the door," he said, adding that money and moral aid would bring a better, long-term payoff.
"We must truly ... work with them to rebalance the world."
Hundreds of Africans hiding out in northern Moroccan forests have rushed Melilla in recent weeks, desperate to scale the barbed wire separating them from European soil.
The Moroccan authorities have been sending the sub-Saharan Africans who have failed to get into Melilla to a desert area bordering Algeria.
Morocco was to deport hundreds of Senegalese on Monday to their homeland.
"[For the EU] to close the door does nothing. They go through the window. They break the door"
MSF's Bernard Kouchner, pushing for money and moral aid instead
People from destitute countries such as Cameroon, Niger, Mali and Burkina Faso try to reach Melilla, one of two centuries-old Spanish enclaves that have Europe's only land frontiers with Africa.
Africans, including Moroccans, also try to cross to southern Spain in small, ill-equipped boats that often sink, if they are not caught by the coast guard.
There are "undoubtedly 4000 dead at the bottom of the sea this year", Kouchner said.