Islamabad is 8 hours behind Wellington
Best overlap: 4:00 PM to 6:00 PM in Wellington is 8:00 AM to 10:00 AM in Islamabad.
For a call that suits both sides, look at 4:00 PM to 6:00 PM in Wellington / 8:00 AM to 10:00 AM in Islamabad. Since Islamabad is 8 hours behind Wellington, the overlap is narrow (about 2 hours); a single, well-protected slot beats hunting for time each week. Finally, Wellington observes daylight saving and Islamabad doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.