Typhoon Koppu is forecast to dump yet more rain on the Philippines' largest island, as authorities said that 16 people had already been killed in the north of the country as a result of the extreme weather.

Meteorological experts on Monday said that with the constant supply of moisture from the South China Sea, Koppu was expected to cause more flooding on the island of Luzon.

Koppu, the second strongest storm to hit the disaster-plagued Southeast Asian archipelago this year, has forced more than 60,000 people from their homes, according to authorities.

The storm, downgraded to a category 1 typhoon from category 4, was moving slowly north on Monday, expected to wander up the west of Luzon.

"With little to guide its course, it looks as though Koppu will wander up the western side of Luzon … for the next two days," Rob McElwee, Al Jazeera's senior weather correspondent, said.

"The projected track of Koppu is close to a worst-case scenario for catastrophic rainfall across northern Luzon, home to more than 10 million people," he said.

Residents of flooded farming villages were trapped on their rooftops on Monday, and animals floated down fast-rising rivers.

Rebuilding efforts

The authorities were working to rebuild damaged roads, bridges and power lines in the areas hit by the storm in order to carry out search and rescue operations.

"We have not reached many areas. About 60 to 70 percent of our town is flooded, some as deep as 10 feet [3 metres]. There are about 20,000 residents in isolated areas that need food and water," Henry Velarde, vice mayor of Jaen town in Nueva Ecija province near Manila, said.

Villages far from rivers in Nueva Ecija were flooded as water from the mountains came rushing down plains and valleys.

"We were not expecting this. Flood waters suddenly swelled around us so we evacuated to higher ground," Reynato Simbulan, a village councillor, told Reuters. He was among hundreds who fled to schools and village halls in Santa Rosa town in Nueva Ecija.

"We are seven kilometres away from the river, but we were still inundated," Simbulan said, adding that massive floods swept away farm animals and some houses made of light materials.

Nearly 183,000 people felt the impact of the typhoon, of whom more than 65,000 had been evacuated from low-lying and landslide-prone areas, the country's disaster agency said.

About 6,000 people were stranded in various ports across Luzon.

Source: Al Jazeera and agencies