Benitez has been impressive in recent weeks after taking time to become fully up to speed fitness-wise following his summer switch from Santos Laguna.
He is forming a promising partnership full of pace with Cameron Jerome who is also looking to find the target for the first time during the current campaign.
The woodwork denied Benitez an opening goal for Birmingham in the impressive home draw with Manchester City on Sunday when Shay Given saved a penalty from James McFadden.
McLeish said: "I can't say it is just a matter of time before the goals come. It would be foolish to say that but I do believe there are goals within these players.
"At the start of the season the pundits said they didn't see where the goals were going to come from at Birmingham but I do know that we have made a lot of chances.
"If we weren't making chances, I would be extremely worried so that gives me a crumb of comfort.
"We have just got to keep working, and be calmer. But Cameron knows he will be judged on goals, Christian knows he will be judged on goals but these lads are doing well and have made us better and we are playing to a very good standard.
"They have to keep working on the training ground every day, believing they will eventually get the goals."
McLeish added: "Is Benitez becoming frustrated? I am hoping it is going to be like waiting for a bus. Once one comes, we get a barrel-load of goals and that tends to happen when you are waiting for a bus.
"I think Benitez has brought something extra to the team. There is no doubt that he upsets defences and I am delighted with his performances.
"To take the pressure off himself, he needs a goal. He will be craving that goal but he doesn't need to worry about his performances. I am very pleased with him."
McLeish has sympathy for the current plight of his Liverpool counterpart Rafael Benitez who is under the microscope after his side have won only one of their last eight games.
But the former Scotland boss is more concerned about making sure Blues remain on the right lines after collecting four points from their last two games.
He said: "I know what people go through when things aren't going well for you. I know the personal turmoil, the pride, and the type of characters I've met in football.
"I know how much pressure they put on themselves, never mind the outside pressure from the media, the fans etc.
"But I've got enough on my plate to be thinking and worrying about anyone else. We are only a bad result or two away from derision and people going against you."
Liverpool 1/3, Draw 4/1, Birmingham 8/1