Philippines officials are warning of a new tropical depression, that is expected to strengthen monsoon rains in the already rain-soaked regions of Southern Luzon, Visayas and Mindanao.
Heavy rain has battered the main island of Luzon for the past two weeks, causing landslides and flooding that has killed at least 85 people.
More than three million people have been affected and as many as 770,000 people have been made homeless.
Associate Director of World Vision Philippines, Mimi Ochavillo, has told Radio Australia's Connect Asia program that while aid agencies are delivering emergency items as quickly as possible, it's a slow process hindered by flood waters that are still knee-deep in some areas.
"The need is still very big, we were only able to distribute to 1,000 families, so the need is still huge," she said.
"That's only to 1 of 31 cities in metro Manila, not talking about the 16 provinces around the country."
Amid the ongoing relief operation, aid agencies are concerned about the outbreak of diseases.
The Philippines Government says water purification tablets are being distributed and mass immunisations carried out to prevent the spread of diseases such as the flu.
Aid agencies have distributed food packs, tanks of clean water and portable latrines to around 950 evacuation centres around the country, but Ms Ochavillo says some evacuation centres are still lacking essential relief items.
With more rain expected, she says the government may need to prepare more evacuation centres.
"We don't need more rain but if that's going to happen, the government will simply find it hard to come up with more makeshift evacuation centres," she said.
"So at this time, we really need to do something about it."
© ABC 2012
19:41 EST Nearly 100,000 people have been displaced by floods in the southern Philippines.