Campbell has scored three times in 14 league appearances this season, helping last term's Championship winners to victories over Manchester City and Swansea City, as well as a draw against Manchester United.
Cardiff sit 15th in the table, four points clear of the relegation zone, following Wednesday's 0-0 draw at Stoke City and Mackay is delighted with his striker's on-going work ethic.
"He's a Premier League centre-forward. He's shown that already this season," Mackay said.
"He works a back four. A centre-forward who's got a work ethic about him is gold dust and you want him to be involved at every point.
"He's someone who has got a great work ethic about him, with his pace and aggression he can make people make mistakes."
Cardiff travel to Crystal Palace on Saturday aiming to pick up their first win in five matches.