It was claimed last week that Juve were hopeful Bonucci, who still has four years left to run on his current terms, would put pen to paper to end speculation over his future.
Moratta has now revealed that talks are ongoing, with the intention of also prolonging teammate Paulo Dybala's contract following his impressive spell in Turin so far.
"The renewals of Dybala and Bonucci - they are two players that have long contracts," he told Premium Sport.
"[But] we are talking with them to see them [extend] again, because it is the players' performance in the team, and because it is right to also adapt them according to the balance within the squad and their place in it."
Chelsea, who are reportedly prepared to pay £60m to sign Bonucci, brought in former player David Luiz on transfer deadline day to ease their defensive concerns.