Before the match a week ago against Slovenia, Argentine players stood behind a banner that read in Spanish: "Las Malvinas son Argentinas" — The Malvinas are Argentine.
FIFA on Friday said it was investigating the case, citing a statute that prohibits "provocative or aggressive actions" and another regulation dealing with team conduct.
Argentine President Cristina Fernandez has used the dispute to gain political support, bringing up a grievance shared by most Argentines.
Britain and Argentina went to war in 1982 over the Falklands in the South Atlantic — an area known as Malvinas in Spanish. Since the defeat Argentina has continued to raise the issue of sovereignty.
Football's world governing body insists the World Cup is a sporting event that should stay clear of politics.
FIFA said Argentina can provide its own evidence in the disciplinary case. It gave no indication of any timeframe or possible penalty.