England international Walker, who has a year left on his City contract, has been one of Guardiola's key players. His versatility allows him to play in a back-four or a back-three.
The defender, who was signed by City for an initial fee of 45 million pounds ($58 million) in 2017, has won 12 major trophies with the English champions, including a historic treble last season.
"He's an incredibly important player for us... His specific qualities are irreplaceable," Guardiola told reporters before Wednesday's pre-season friendly between the two clubs.
"We want him, yes, in the end. I don't know what will happen. I know we're in contact, both clubs. We will fight for him like I'm sure Bayern will... I don't know how it will finish."
Asked if Walker would feature against German champions Bayern in Tokyo, Guardiola said: "We need our best players out there against Bayern and we hope he is going to stay with us next season, so why should he not play?"
City's first match of the 2023-24 domestic campaign after their pre-season tour is the Community Shield game against Arsenal on August 6.
