Asked about possible plans to extend the elite Champions League at the expense of the second-tier Europa League, Platini said: "There is an ongoing debate to determine what form the European competitions will have between 2015 and 2018. We're discussing it, we will make a decision in 2014. Nothing is decided yet."
One of the options being looked at is the possibility of extending the final phase of the Champions League from 32 to 64 teams.
The Europa League generates far lower revenue for clubs than the Champions League and has been criticised since it evolved from the UEFA Cup in 2009.
Meanwhile, the UEFA president said that he was not worried by talk of the creation by Europe's rich clubs of a competition to rival the Champions League.
"It's a question that is regularly brought up," said the former French midfielder.
"It doesn't worry me. I can't see how it could work outside the UEFA framework. Who will referee them? In what stadiums will they play? A lot of people want them? I don't think so."