Most of the victims were swept away by rampaging floodwaters and drowned or were hit by debris-laden mudslides in three towns in hard-hit Maguindanao province.
Landslides and flooding in the southern Philippines have killed at least 67 people, according to an official tally, with rescuers racing to save residents of a mountain village that was buried in mud.
The village of Kusiong accounted for many of the 50 deaths in the area around Datu Odin Sinsuat town, after heavy overnight rain unleashed floods mixed with mud, rocks and fallen trees that buried the community, the area's civil defence office said in a statement on Friday.
Similar avalanches also struck villages in the nearby towns of Datu Blah Sinsuat and Upi, which accounted for 17 more deaths.
Eleven people remain missing and 31 were injured, according to official figures.
Flash floods from rains wrought by Tropical Storm Nalgae swamped nine mostly rural towns around Cotabato, a city of 300,000 people on Mindanao island that was also submerged in widespread flooding.
Many residents were caught by surprise as floodwaters rose rapidly before dawn, Naguib Sinarimbo, the spokesperson and civil defence chief for the regional government, said.
Teams in rubber boats had rescued residents from rooftops in some towns, Sinarimbo said.
READ MORE: Venezuela expects landslide death toll to reach 100
Floodwaters have receded in several areas, but Cotabato remained almost entirely waterlogged.
Sinarimbo said there could be more flooding over the next few hours because of heavy rain over mountains surrounding the Cotabato river basin.
The army deployed its trucks to collect stranded residents in Cotabato and nearby towns, provincial civil defence chief Nasrullah Imam said.
"It was a shock to see municipalities which had never flooded getting hit this time," Imam said, adding that some families were swept away when the waters hit their homes.
The heavy rainfall began late on Thursday in the impoverished region.
The state weather office in Manila said the downpours were partly caused by Nalgae, which it expects to strengthen at landfall overnight Friday.
Nalgae headed northwest over water with maximum winds of 85 kilometres (53 miles) an hour just off Samar island late on Friday and is forecast to track the Bicol peninsula early Saturday.
More than 7,000 people were evacuated from flood- and landslide-prone communities in these areas, the civil defence office said in an updated tally.
The coast guard also suspended ferry services in much of the archipelago nation, where tens of thousands of people board boats each day.
Scientists have warned that storms, which also kill livestock and destroy farms, houses, roads and bridges, are becoming more powerful as the world gets warmer because of climate crisis.
READ MORE: Peru landslide buries alive man, one-month-old baby