Typhoon Koppu, which claimed at least nine lives and affected over 25,000 people in the Philippines, was on Monday weakening although more than 20 provinces were still on high alert, official sources here said.

Koppu made landfall in Luzon island in the early hours of Sunday morning at super typhoon strength, ripping the roofs off buildings and uprooting trees in the coastal province of Aurora.

The typhoon, moving at a speed of just five kmph, was expected to weaken into a tropical storm and leave the Philippines in the next few days, possibly Tuesday, the Philippine Atmospheric, Geophysical and Astronomical Services Administration said.

Local government officials of the affected regions have so far reported at least four people dead, EFE reported.

The National Disaster Risk Reduction Council earlier on Monday reported two people were killed and five injured.

The figures are expected to increase considerably given that the situation in numerous remote areas remained unknown.

According to latest figures by the Department of Social Welfare and Development, around 203,000 people have been affected by Koppu of which close to 60,000 were receiving aid outside evacuation centres.

Antonio Lustre, the mayor of San Antonio in the Nueva Ecija province, said his town was under water and people were waiting to be rescued from the rooftops of their houses.

The heavily populated region around capital Manila was not in Koppu's direct path, but it was still getting lashed by winds and rain.

The deadliest storm to hit the country in recent years was super typhoon Haiyan, which left more than 7,000 people dead or missing in November 2013.