Benzema showed his potential with two hat-tricks in December, but Madrid playmaker Kaka believes the 23-year-old needs to do more.
The Brazilian said at a promotional event: "He (Benzema) is a great forward, but he sometimes isn't completely involved in the game.
"I think he could do a little more and that's what the people expect. But we see his quality in training. He can be an important player for Real Madrid but it depends on him."