Tom was in charge of the league game between Sundowns and Polokwane City at Loftus Stadium on Tuesday and blew for many fouls, much to the frustration of Mosimane.
The young official also opted against awarding a penalty after one of the City players was brought down by midfielder Tiyani Mabunda inside the 18-yard area.
However, Mosimane believes Tom will improve with time as he continues to officiate in lower-profile matches.
"He is a young referee. He needs to get games like this to improve," Mosimane said after the 1-1 draw.
"There were a little bit of fouls that he gave in the first half more on Polokwane City because the game was congested in the midfield with Jabu [Maluleke] playing on tight angles, one-twos, sometimes he falls and they got fouls there. If it's Champions league it's a totally different game.
"Like [Victor] Hlongwane, you know that he lets the smaller things go, he lets the game go, but this one [Abongile Tom] is whistle-happy... tswiri tswiri every minute. I mean really. I don't say it's not fouls but he loves the whistle.
"He stops the game so many times. He is whistle-happy. He is happy to blow. Anyways let's give him a chance to grow," he added.