The tremor was registered at 06:11 GMT 3 miles southeast of Magsaysay town. Previous reports indicated that a 6-year-old girl was killed due to the quake, while 37 others were injured.
The Philstar Global newspaper reported that rescuers recovered six more dead bodies in the collapsed supermarket in Padada town on Monday, while rescue operations continued.
Earlier, there had been a report of three people killed.
At least 179 aftershocks were registered in Davao del Sur province in the first four hours after the quake.