Academy graduate Harwood-Bellis has been with the Citizens since the age of six, but the 20-year-old has recently had experience out on loan with Blackburn Rovers, Anderlecht and Stoke City, making 24 appearances for the latter in 2022.
Twenty-five-year-old Itakura, meanwhile, has enjoyed loan spells with both Groningen and Schalke 04, making a combined 91 appearances, but the versatile defender is yet to play for Man City since joining the club in 2019.
According to Sky Sports News, Ange Postecoglou is looking to bolster his defensive options this summer and he has identified both Harwood-Bellis and Itakura a potential targets.
The report adds that a move for either defender would have no impact on their efforts to make Cameron Carter-Vickers' loan deal a permanent transfer from Tottenham Hotspur this summer.
Celtic have recruited a number of players from Man City in recent years, including the likes of Jason Denayer, Patrick Roberts, Dedryck Boyata and Olivier Ntcham, and they believe that their relationship with the Citizens could help in their pursuit of Harwood-Bellis.
As for Itakura, Schalke are struggling to afford the £6m fee they agreed with City last summer, which could pave the way for Celtic to make a move for the Japan international, who they have been monitoring for the last 12 months.