There were no immediate reports of serious casualties but electricity was cut and water pipes ruptured in Lanao del Sur, a mainly rural region some 800 kilometres south of Manila, they said.
The quake struck at 5:21 am, sending residents jumping out of bed and running onto the road to avoid falling objects, disaster officials said.
"Residents are really shocked with regard to the calamity that happened. So they are on standby (at) the highway," provincial disaster official Francis Garcia said over ABS-CBN television.
The state seismology office said the quake was felt in 16 other cities and towns in the south including the major urban centres of Davao and Cagayan de Oro.
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Francis Magbanua, an ABS-CBN reporter based in the south, tweeted a photo of a television set on the floor that he said had fallen off the wall of his house.
"Our appliances fell from the (wall) racks," he said.
The state seismology office said a highway had a crack while wooden houses, a national high school and a mosque sustained minor damage.
"Since the (Mabini) quake, our people became more aware to duck, (take) cover and hold," Kristofferson Vidad, science research assistant at the seismology agency, told AFP, referring to its standard advice on surviving quakes.
The Philippines lies on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent earthquakes and volcanic activity.
A 6.5-magnitude quake killed eight people and left more than 250 injured outside the southern city of Surigao in February, and another 5.9-magnitude tremor killed one person there last month.