Moody has left his role as Mackay's head of recruitment and been replaced by 23-year-old Alisher Apsalyamov, who is thought to be a friend of Cardiff owner Sri Vincent Tan's son and has little experience in football.
The decision to employ Apsalyamov appears to undermine Mackay's position and Bellamy is keen to show his support for the City manager.
"Iain is a huge loss for us, a huge, huge loss because he is outstanding," he said.
"Any club with Iain Moody is a miles better club, without a shadow of a doubt."
The striker says he rates Mackay as one of the brightest talents in the Premier League and has backed him to bring more success to Cardiff.
"As a manager Malky is the best young British manager out there and what he's done for this club in a short space of time is nothing short of remarkable," he added.
"We've got a group of players and fans who are united - and he's done all that.
"He's responsible for the connection between the fans and the players.
"We are such a tight-knit group now, the discipline he has brought into this club is remarkable.
"I'm just a player, I can only talk from a player's point of view and I can't try and dictate to anyone above me but the simple fact is I am very fortunate as a player to be working with the guy.
"He's certainly brought everyone together at Cardiff and we needed that.
"That's not being disrespectful to the managers who were here before him but he's taken it on to another level.
"He's united the city and being from Cardiff that makes me feel very proud."