Fighting in the troubled southern Philippine region of Mindanao has combined with extreme weather events to create a "humanitarian catastrophe", French aid groups said Wednesday.
Around one million people have fled their homes in the region, according to Thibault Henry, head of the Philippines chapter of the charity Acted.
"Basic needs are not covered," Henry told AFP.
"Clearly it's a huge humanitarian crisis, a catastrophe, that will affect the region for many years," he said, noting that more than half of the population lives in poverty.
In early July a top government official estimated the number of displaced at 400,000.
The Moro Islamic Liberation Front (MILF), the Philippines' largest Muslim rebel group, and government forces, with US military backing, are battling militants who support the Islamic State group (IS) in the region.
Hundreds of IS supporters occupied parts of the city of Marawi in late May in a conflict that has claimed more than 700 lives.
Mindanao was struck by typhoons in 2012 and 2013 and a drought in 2016, Henry noted, adding that other rebel movements affected other parts of the region.
Vanessa Cardamone of Handicap International said conflict combined with extreme weather events had created a "complex crisis".
She said only six percent of those displaced are in camps, while most are lodging with private individuals.
For his part Javad Amoozegar of the French charity Action Contre la Faim said humanitarian aid is falling far short of needs.
"The Philippines is at the bottom of the list... forgotten by the news," he said. "Most donors look at the number of victims before mobilising. Here the people aren't dead yet, but we want to help them so they don't die."
The 10,000-strong MILF has been leading a decades-long rebellion to establish an independent or autonomous homeland in Mindanao for the mainly Catholic Philippines' Muslim minority.
Hardline militants including former MILF members oppose any form of peace with the government, and some have in recent years pledged allegiance to IS.
The MILF has repeatedly warned that if the peace process collapses it will lose many of its younger members to IS-aligned groups.