Many victims were swept away from low-lying residential areas when the flash floods and landslides struck.
More deaths were reported in Bukidnon, Iligan and Misamis Occidental.
Andrew Morris, from the UN children's agency Unicef in Mindanao, said in some areas there were big risks of disease, particularly for children, and restoring clean water supplies would be a priority.
"Lanao del Sur province is the poorest in the Philippines, and in the past seven months there have been around 350,000 people displaced in that province because of fighting," he told the BBC, referring to battles between government forces and Islamist militants in Marawi.
Meanwhile, Richard Gordon, of the Philippines Red Cross, told the BBC: "We have already provided water and hot food.
"And we're going to be distributing non-food items - certainly blankets, mosquito nets and certainly hygiene kits for those who are in evacuation centres so that we can alleviate the suffering of many of the folks there." Sky more