The Turkish international, who is on-loan with Rovers for the season, started the campaign in red-hot form with goals in his first two games, but having returned from a knee injury in recent weeks he hasn't quite hit the heights shown at the beginning of the season.
In the games against Bolton Wanderers and Cardiff City Kazim-Richards showed glimpses of his previous form when providing assists in both games and now Berg wants to see it on a more regular basis.
"I think Kaz has done really well in games when he has come on for us," said the Rovers boss.
"But we need him to be like he was in that second half every time, all the time, and if he is that then it is not a problem, but we need him to play at that level every time.
"We know his potential and he showed it when he came on against Bolton, he showed it when he came on against Cardiff and that is good to see and that is what we would like to see every time he plays whether he is starting or coming on."