"Twenty-four is ok...I think it's ok. Eight good teams to add. It's not a problem of quality," Platini said, looking ahead to France 2016 after giving a glowing assessment of the ongoing tournament in Poland and Ukraine.
Euro 2012 has provided plenty of goals and entertainment in the 22 matches to date and approaching the end of the group stage is yet to feature a goalless draw.
Fears have been raised that adding eight teams to the tournament will see middle and lower-ranked sides qualifying and resorting to overly defensive tactics, looking to avoid humiliating defeats at the hands of the major European powers.
"We can have eight more teams as good as the rest, and also have a fantastic round of 16," added Platini.
"It's very important for the (additional) countries that qualify. It is good for the national associations and their development.
"The sponsors are present because they are proud to participate."
Platini said more teams meant "more games in stadiums which leads to better investment".
The Frenchman pointed to the examples of Ukraine cities Lviv and Kharkiv, which invested millions in stadiums and infrastructure but are staging just three group matches apiece, as an example of where host cities in future tournaments will benefit from more games.
"How can we ask to a city like Lviv to build an airport, to build a big stadium, and after three games it is finished for the Euro?"
Three-times European champions Germany have said they have "mixed feelings" over the expansion of the tournament.
The European Championship started as a four-team tournament in 1960, expanding to eight in 1980 and 16 in 1996.