UEFA have given the Balkan nations an official warning due to the misbehaviour of their fans and Serbia face a fresh charge after the ugly scenes at the end of the England Under-21 match in Krusevac last month.
Platini admits he is keeping a close eye on the two countries and will ban them from Brazil 2014 if there is further crowd trouble in their remaining Group A ties.
Scotland are currently bottom of the table, a position that led to the recent sacking of manager Craig Levein, but they would be handed a lifeline if the two teams are eliminated.
Platini told the Daily Record: "More than a year ago we gave a serious yellow card to Croatia and to Serbia.
"It's true it's a problem that concerns us hugely. I personally will attend the games and evaluate what the Croatian and Serbian Governments are doing with the problems.
"If we get firecrackers, banned flags and racist chanting then they will be removed from the World Cup in Brazil."