The U.N. Children's Fund estimates that more than 50 people were killed or injured from land mines or other ordnance in Mali from last March through December.
Marc Vaillant, a program office with the U.N. Mine Action Service, said in a statement that much of the weapons were left over from conflict between northern militants and Malian forces.
"It is very likely that this figure is actually much higher," he said. "The problem is indeed serious."
Control over northern Mali was lost to foreign rebels and fighters loyal to al-Qaida in January following a coup in Bamako. The Malian government last month called on former colonial power France to help thwart the southern advance of militant forces.
UNMAS said it started a five-week training program to help members of the Malian military and police with demining efforts. The agency said mine contamination along the Malian border with Algeria is widespread, but stressed most of that was from before the French intervention.