El Zamalek, Zaki's club side, are reluctant to let him go after his five-star display in a cup final last weekend.
Wigan football director John Benson was in Cairo watching the game and was hoping to complete a deal this week.
El Zamalek officials say they intend to retain Zaki until a suitable replacement is found but admit this will be no easy task.
Wigan had thrashed out a year-long loan release for Zaki with a view to the move becoming permanent if both parties were happy with how things went at the JJB.