By Agence France-Presse
The quake struck southeast of Davao City at a depth of 59 kilometres (35 miles), the US Geological Survey said, while the Pacific Tsunami Warning Centre said "hazardous tsunami waves from this earthquake are possible" along the coasts of Indonesia and the Philippines.
However tsunami waves were forecast to be less than 30 cm (12 inches) high, the Pacific Tsunami Warning Centre said.
The Philippines' government seismology office said cities in the south of the country felt "moderately strong" shaking.
The provincial civil defence office said it had no immediate reports of damage or casualties from the quake.
According to the USGS, there was a low likelihood of casualties and damage, although it warned recent earthquakes in the area had caused landslides.
The Philippines and Indonesia lie on the so-called Ring of Fire, a vast Pacific Ocean region where many earthquakes and volcanic eruptions occur.
The most recent major quake disaster to strike the Philippines was in 2013 when a 7.1-magnitude quake left more than 220 people dead and destroyed historic churches in the central islands.
Indonesia has been hit by two major tsunamis this year. More than 400 people were killed last weekend after an erupting volcano triggered a deadly wave that struck the coastlines of western Java island and south Sumatra.
A quake-tsunami in September killed around 2,200 people in Palu on Sulawesi island, with thousands more missing and presumed dead.