Manager Manuel Pellegrini is still keen to bolster his defensive options and, according to the Daily Star, Mangala is the target.
City are willing to battle for the 22-year-old's signature, with Premier League rivals Manchester United and Chelsea also believed to be interested.
Mangala revealed that City made a late surge for him in the window, but admitted that a move was never close.
Instead, City turned to Martin Demichelis but were dealt another blow when the Argentine centre-back was ruled out for six weeks with a knee ligament injury.
This has reportedly forced City to plan a bid for Mangala when the window re-opens.
Mangala, who joined Porto in 2011, is thought to have a release clause of around £40m.