The 31-year-old has been strongly linked with a move away from Real Madrid after having fallen down the pecking order at the Bernabeu.
Kaka joined Real Madrid from AC Milan in 2009.
Allegri said: “If he was to come, AC Milan would be stronger because he is a player with great quality.
“We would need him and he would offer a great contribution from a technical and charisma point of view, even though he hasn’t played a lot in the last two seasons.
“I am confident in what the club will do in the last days of the market.”
