Heavy rain swamping the southern Philippines has left four people dead and affected 250,000 others, officials said Wednesday.

The rains over the past five days have flooded entire towns and caused landslides across vast areas of the mainly rural south, with more bad weather forecast for the rest of the month.

"What we are having now is a creeping disaster," the head of the state weather service, Graciano Yumul, told reporters in Manila.

Yumul said Surigao, a city of 120,000 people, had received 1.8 metres (nearly six feet) of rain in one day.

Two farmers drowned on Monday and another on Friday when they were swept away while crossing swollen rivers near Surigao, June Parada, spokesman for the provincial government of Surigao del Norte, told AFP.

A seven-year-old boy also drowned in a neighbouring southern province, according to the National Disaster Risk Reduction and Management Council in Manila.

The government was rushing rescue equipment and emergency aid to nearly a quarter million people affected by the floods and landslides, it added.

It was the second time the region had been hit by torrential rains this year.

Flooding across the southern and central Philippines last month claimed 75 lives, according to the disaster council.