"It will certainly not be an easy game for us because we are missing eight key players who did not show up when they were called, but I hope my boys will put up their best," the veteran French coach said.
The absentees include former captain Lomana LuaLua (pictured) and Anderlecht striker Dieumerci Mbokani but Leroy, who won the African Nations Cup as Cameroon coach in 1988, feels his side could still upset the odds in the opening Group I qualifier.
"Cameroon do not have the same quality players as when I was here," he added.
"All the same, I know they will put up a hard battle as most of the players are professionals in Europe and have a strong fighting spirit. So, things shall not be easy for us but we shall do our best."
DR Congo, then known as Zaire, qualified for the 1974 World Cup finals in West Germany but have seen their fortunes plummet in recent years and were 124th in the latest FIFA rankings.