Access for aid workers is already precarious in the north, where 500,000 people - half the remaining population - depend on foreign aid, ICRC President Peter Maurer said.
Military experts from Africa, the United Nations and Europe have drafted plans to recapture northern Mali, which fell to rebels in March after a coup in the capital Bamako led to a power vacuum.
Maurer urged foreign leaders to bear the humanitarian cost in mind as they planned action.
"There is a lot of talk how to 'liberate' the north, how to reconquer the north, but there is little consideration of what the humanitarian impact of whatever scenario would be," Maurer told a news briefing.
"It remains a vulnerable region in terms of food security anyway, it has always been. But compounded with the insecurity of the politics and military planning, this becomes particularly dire and particularly sensitive," he said.
Maurer said that he had discussed the issue during visits to Mali, Niger and at a closed-door session of the African Union's peace and security council in Addis Ababa in October.