Striker Green has moved to Birmingham on a two-year deal from Conference Premier champions Mansfield Town, but Clark has backed the 26-year-old to score regularly for the St Andrew's outfit.
The 40-year-old told the Birmingham Mail: "I want him to have the belief that he belongs here. He's deserved this opportunity and I've got every confidence in him.
"I'm looking forward to working with him and he'll score goals.
"I just think that when you are a goalscorer, wherever you are playing at, when you have got those natural instincts, you can score goals at any level."
The former Oxford United player scored 27 goals for Mansfield last season.