The quake hit 70 km north of the city of Dumaguete on Negros Island at 11:49 am (0349 GMT) at a depth of 20 km, the US Geological Survey said.
The Philippine Institute of Volcanology and Seismology issued a tsunami alert for a metre high wave along the east coast and west of Cebu City.
The Pacific Tsunami Warning Center said a regional tsunami was not expected.
However, it said on its website that earthquakes of this intensity can sometimes trigger destructive local tsunami.
The late morning quake in the Negros and Cebu region caused panic in nearby cities, with people rushing out of schools, malls and offices. Officials in some areas suspended work and cancelled classes.
A child was crushed to death by a collapsed wall in Tayasan town in Negros, Benito Ramos, chief of the Office of Civil Defence told reporters.
Buildings in the cities of Cebu and San Carlos shook violently and sustained damages such as broken windows and cracks on the walls, he added.
Two aftershocks measuring 4.8 and 5.6 magnitude on the USGS scale followed within half an hour of the earthquake.