The epicentre of the quake was 72 km southwest of Khuzdar in Balochistan province, according to the US Geological Survey. The quake struck at a depth of 24.9km, Express News reported.
No loss of life or property was immediately reported. Meteorologists said the tremors were felt in Khuzdar, and towns in Awaran and Kharan districts, located near the epicentre of last month's 7.7-magnitude quake that killed nearly 500 people and left 100,000 others homeless.
It was Pakistan's deadliest quake since the 2005 devastating Kashmir tremor, which killed 73,000.
Southwestern Balochistan is Pakistan's largest province with large oil and gas reserves, but it remains impoverished and affected by political instability and a nationalist insurgency.