San Pedro residents continue to use makeshift boats to get through the floodwaters left by two storms that struck the Philippines. (Romeo Ranoco/Reuters)

Officials told residents still reeling from mudslides that recently buried hundreds in the northern Philippine mountains to be ready to abandon their homes again if a storm approaching Friday becomes the third typhoon in a month to hit the country.

The warning came after back-to-back storms since Sept. 26 caused the worst flooding in 40 years in and around the capital Manila and unleashed landslides in the Cordillera Mountains in the north of the country, killing 773 people and affecting more than seven million.

Tropical storm Lupit may intensify into a super typhoon by the time it makes landfall next week with winds up to 230 km/h, forecasters said. It was expected to enter Philippine waters late Friday.

"We are still retrieving our dead and here comes [Lupit]," Gov. Nestor Fongwan of Benguet province said in a radio interview. "I hope it does not hit us."

At least 288 people were killed in last week's landslides in Benguet province.

The new storm may spare the saturated northern Philippines and veer toward Taiwan early next week, or may track the same devastating path as Typhoon Parma, which made landfall Oct. 3 then lingered for a week while battering the main northern island of Luzon, said chief weather forecaster Nathaniel Cruz.

Pre-emptive evacuation

Disaster-relief officials in the Cordillera region advised thousands of residents to be prepared to move to safer ground to avoid the threat of mudslides that last week buried dozens of mountainside houses with entire families, blocked roads and isolated towns for days.

A man cooks his meal on a charcoal stove on top of a table to avoid flood waters in Pasig City, Philippines, on Friday. (Pat Roque/Associated Press)

"We are informing them that there's an incoming typhoon and that we must be aware of the necessity for pre-emptive evacuation once we know that we will be hit," said Olive Luces, head of the Office of Civil Defence in Baguio city, 210 kilometres north of Manila.

With the jagged terrain in the region of more than 1.2 million people, Luces said that large swathes of land may be considered danger zones. Residents living in low-lying areas, near cliffs and mountain slopes will be priority targets for evacuation, she said.

The Joint Typhoon Warning Center, operated by the U.S. navy in Hawaii, projected the storm may make landfall Wednesday in northeastern Isabela or Cagayan provinces and exit the Philippines through northwestern Illocos provinces the same day.

Health officials warned there has been an upsurge in leptospirosis, a disease spread through exposure to water contaminated with the urine of infected animals, in parts of the country still submerged in flood water.

Health Secretary Francisco Duque said 1,027 leptospirosis cases and 89 deaths were recorded in Manila alone from Oct. 1-15.

More cases were expected because up to 1.7 million people were still exposed to floods, he said. Last year, about 800 cases were treated nationwide and about 60 people died.