Manila  - The Philippine weather bureau warned Friday that a tropical storm bearing down on the country could strengthen into a "supertyphoon" before hitting the northern provinces.

Tropical Storm Lupit was forecast to enter the Philippines' area by Friday evening and could make landfall early next week.

Nathaniel Cruz, the bureau's chief weather forecaster, said Lupit would batter the same areas devastated by Typhoon Parma and Tropical Storm Ketsana in the past three weeks.

At least 773 people have been killed by Parma and Ketsana with 88 still missing, according to the National Disaster Coordinating Council.

The council said more than 7 million people were affected by floods and landslides caused by the back-to-back storms.

Cruz said Lupit was moving west-north-west at 26 kilometres per hour. It was packing maximum winds of 65 kph and gusts of up to 80 kph.

He urged the public to prepare for "an intense typhoon" as Lupit was expected to gain strength as it travels toward the Philippines.

"It can reach almost the supertyphoon intensity before hitting land, if and when there will be no change in its course, direction and speed," he said.

Cruz said the best-case scenario was Lupit would change course and move toward Taiwan or Japan without causing damage to the Philippines.

Ketsana first slammed into the Philippines on September 26, causing the worst floods in more than 40 years in Manila and nearby provinces.

One week later, Parma struck and spawned heavy rains for almost one week that triggered massive landslides and floods in northern provinces.

Authorities said damage to agriculture and infrastructure were estimated at more than 21 billion pesos (462 million dollars). (dpa)