City have endured ongoing struggles in the left-back role this season, a problem area that has been largely neglected in recent windows.
Speaking to the media, Guardiola identified the position as a key priority, though he declined to specify the number of signings expected overall.
"Obviously. Nico (O'Reilly) is helping us, but he's not a left-back. That's true. I played with Alex Zinchenko at left-back, Fabian Delph at left-back," said Guardiola.
"We found solutions in many, many years, and with other qualities they help us.
"Alex and Fabian for example, or sometimes Rico (Lewis) when I play the full-backs left, they help us massively. But yeah, of course we don't have... of course we can have Nathan (Ake), but Nathan - like John Stones - has been injured all season."
Behind the scenes, the club's summer strategy is already taking shape. Hugo Viana, who began working full-time at the Etihad Stadium earlier this month, is heavily involved in the planning process alongside current director of football, Txiki Begiristain.
Viana is set to take over from Begiristain in the role this summer, marking a significant change in City's football operations leadership.
The transfer window is expected to be a busy one, with both arrivals and departures anticipated within the first-team squad.
In addition to the left-back position, the club faces the challenge of identifying a successor to Kevin De Bruyne, with the Belgian playmaker's long-term future in the side uncertain due to fitness and form concerns.