Torrential rains are expected to inundate the northern island of Luzon even before Typhoon Koppu makes landfall early Sunday, the country's acting weather bureau chief Esperanza Cayanan told reporters on Saturday.

Koppu is moving at 10 kilometers per hour, and could strengthen as it gets closer to the land.

The typhoon will not leave the archipelago until Tuesday as another typhoon in the east and high pressure in the country's north will hold Koppu in a "semi stationary" state for many hours, according to Cayanan.

"We are looking at the possible worst scenario, not to scare but to allow us to prepare," Cayanan said about Koppu, which will possibly be the second most powerful storm to hit the disaster-prone country this year. "If it stays 24 hours … and the downpour is sustained, we will surely have floods and landslides," she added.

Civil defense authorities said the typhoon would not directly hit the capital Manila but southern regions of the country were likely to be affected due to its huge diameter.

Areas directly hit by Koppu will endure "heavy to intense rains" and possible tsunami-like storm surges in the coastal areas. The authorities have banned all vessels from sailing in the sea.

President Benigno Aquino said Friday the government would ensure the safety of the people. It was the first time that Aquino has personally issues a storm warning since Typhoon Haiyan devastated the central Philippines in November 2013, killing more that 7,300 people.

"Your government is here in order to ensure that we will meet our goal of zero casualties," the president said on TV. "But I must emphasize that each local government unit, community, and Filipino that will be affected has the duty to cooperate … to overcome the challenges ahead."

shs/rc (AFP, AP)