"It will be much more," Sohail ur Rahman, the top civilian official in one part of Baluchistan, told Dawn News TV station.
Rahman said at least 80 people had been killed and some 500 houses had been destroyed.
Pakistan's army said it was rushing medical teams on helicopters to villages in the affected areas.
The quake struck two hours before dawn and had a preliminary magnitude of 6.4, the U.S. Geological Survey reported. It was a shallow 10 miles below the surface and was centered about 400 miles southwest of the capital, Islamabad.
Pakistan is prone to violent seismic upheavals. In October 2005, a magnitude-7.6 quake devastated Kashmir and northern Pakistan, killing about 80,000 people and leaving hundreds of thousands homeless.
Baluchistan is home to a long-running separatist movement, but is not considered a major battle ground in the fight against Taliban insurgents that plague other border regions.
Associated Press writer Matiullah Achakzai contributed from Chaman.