The 48-year-old claims the Bosnian would score between 20-30 goals in the Italian top flight and reiterated that Edinson Cavani has been a long-term target at the Etihad Stadium
City is willing to use 27-year-old, who Mancini signed from Wolfsburg in January 2011, as part of its bid to sign Napoli forward Edinson Cavani this summer.
Mancini started Dzeko just 16 times in the Premier League last season, fewer than both Carlos Tevez and Sergio Aguero, but the former City boss claims the Bosnian would be one of the leading striker's in the Italian top flight.
"Dzeko is a great striker and in Italy he could score 20-30 goals for the season," Mancini told reporters.
Earlier this month, Chelsea entered the race with City and Real Madrid for Cavani after offering Fernando Torres to Napoli in a 63 million euro player-plus-cash bid for the 26-year-old.
City's own move for Cavani has stalled, while Mancini reiterated the Uruguay international was one of his targets during his reign at the Etihad Stadium.
"When I was at Manchester I talked often with the board about Edinson Cavani because he could interest us a lot," he said.
"Right now I don't know if they have still interest in him with the new technical project."