Dear Lakshmi,
Superannuation age must be mentioned in joining letter, without which company can not enforce retirement policy on employee on its own. However, if you are not satisfied with the performance of the individual due course of action can be taken. If the individual is not performing up to the expectation of the management, same can be conveyed to him. If his performance / attendance, etc are affected by his age, then same can be used to ask him to move out. Since you have mentioned he is regarded high by the management, you should consult them before taking any action. I recommend HR should handle such cases with lot of poise and dignity, since any improper action will signal other employees that company does not care for commitment in the longer run.
Sunil Kumar