The bus was heading to Karachi from Bela, a district of Balochistan. Earlier in the day, at least 57 people including women and children were killed when their bus crashed into an oil tanker, igniting a fierce blaze near Super Highway.
Rescue source confirmed death of five people including three children. Sources said the incident occurred due to speeding.
The injured and bodies were being moved to Karachi.
The bus, which met an accident occurred earlier in a day, was en route to the town of Shikarpur from Karachi when the collision occurred.
Initial reports indicated the oil tanker was on the wrong side of the road along a dilapidated stretch of highway, police said.