The manager is concerned by the delays, with the likes of Manchester City and Serie A outfit Inter reportedly interested.
Sagna's current deal at the Emirates Stadium will expire at the end of the season, meaning he can depart the club on a free transfer if fresh terms are not agreed to.
"Talks are not progressing," he said ahead of Monday's encounter with Newcastle United. "The ball is not in our court anymore and he has to come back to us [with an answer]."
While Sagna could be heading for the exit door, Wenger was also asked about incomings and the possibility of a deal for striker Loic Remy, who is currently on loan at Newcastle from QPR.
But Wenger refused to be drawn on whether a move was imminent, adding: "He is a good striker. But we are focused on the end of the season, not on strikers."
Wenger also confirmed that midfielder Abou Diaby will not take part Monday. The Frenchman played 45 minutes of a reserve fixture midweek after 13 months on the sidelines due to a cruciate ligament injury.
However, his return to the first team has been curtailed by a groin problem.
"[Diaby] had a little groin problem after the game so will not be available on Monday," Wenger said.