A heatwave in Pakistan's largest city Karachi and other districts of southern Sindh province has killed at least 122 people, health officials said Sunday.

"Since Saturday 114 people have died in Karachi and eight others (have died) in three districts of Sindh," provincial health secretary Saeed Mangnejo told AFP.

The southern port city saw temperatures reach as high as 45 degrees Celsius (111 degrees Fahrenheit) on Saturday, just short of an all-time high in the city of 47 C in June 1979.