The death toll from a powerful earthquake in the southern Philippines has risen to three, official tallies showed Monday, as frequent aftershocks send residents fleeing into the streets. 

At least eight people have also been injured since the magnitude 7.6 quake hit Saturday off the coast of Mindanao island, in an area that has seen a series of aftershocks of magnitudes exceeding 6.0 through Sunday.

A magnitude 6.9 quake hit the area early Monday at a depth of 30 kilometres (18 miles), about 72 kilometres northeast of Hinatuan municipality in Surigao del Sur province, the US Geological Survey said.

"Up to now we're still terrified because there are many aftershocks," Alex Arana, head of the province's disaster agency, told broadcaster DZBB.

As of Sunday night, more than 30,000 families were staying in evacuation centres in Surigao del Sur, Arana said. 

Josephine Ungab, 54, and her three children spent Saturday night in an evacuation centre in Hinatuan, about 21 kilometres from the epicentre of the initial quake. 

They returned home the next day but were back at the shelter on Monday after another strong tremor. 

"Every time that there is an earthquake we feel restless," she said. 

"It is as if our house will be destroyed by the quake and waves."

Some walls and roads cracked while more than a hundred homes were destroyed and the roof of an outdoor court collapsed. 

Monday's quake was "quite strong" but people did not panic this time, said Allan Luna, a disaster officer in Cagwait municipality.

"Since they've experienced a similar quake already, they calmly went out of their houses and stayed outdoors for around an hour," he said.

Hinatuan police Staff Sergeant Joseph Lambo said a quake on Sunday evening — which USGS said was magnitude 6.6 — sent people rushing out of their homes again.

"They were panicking due to the memory of the previous night's quake," Lambo told AFP.

Saturday's quake briefly triggered tsunami warnings across the Pacific region and sent residents along the east coast of Mindanao fleeing buildings, evacuating a hospital and seeking higher ground.

Collapsed wall kills man

Two people died in Surigao del Sur, Arana said — one from falling debris and the other from a wall collapsing on top of him. 

A pregnant woman was killed in Tagum city in Davao del Norte province, the national disaster agency said, without providing details. 

Arana said eight people were injured in his province.

The Philippine seismology institute said Saturday's quake was generated by the movement of the earth's crust along the Philippine Trench. 

The long, narrow depression on the eastern seaboard of the Philippines forms the boundary of one tectonic plate pushing against another. 

"The frequent aftershocks are produced by the continuous adjustment of the rocks that moved and caused the earthquake on Saturday," the institute said, warning aftershocks could continue for several weeks.

The recent earthquakes came about two weeks after a 6.7 magnitude tremor hit Mindanao, killing at least nine people, shaking buildings and causing part of a shopping mall ceiling to collapse. 

Earthquakes are a daily occurrence in the Philippines, which sits along the Pacific "Ring of Fire", an arc of intense seismic and volcanic activity that stretches from Japan through Southeast Asia and across the Pacific basin.

Most are too weak to be felt by humans.