Nock-ten was expected to hit the heavily populated central section of the main Luzon Island at, then dump heavy rain there for about a day before blowing out into the South China Sea, the state weather service said.
The storm hit the coastal provinces of Albay and Camarines Sur on southern Luzon on Tuesday, forcing 645 000 people to flee their flooded homes, National Disaster Risk Reduction and Management Council chief Benito Ramos said.
"Those two provinces are underwater," he said.
The government is waiting for the skies to clear and the seas to calm down before sending emergency supplies by air and water to those provinces, according to Ramos.
"We can't use the army trucks because the roads are flooded," he said.
The council said dozens of flights had been cancelled because of the storm.
Ramos said 14 people had been confirmed killed so far, with most of the fatalities in the coastal regions.
More than eight million people live across the central plains of Luzon, where Nock-ten is forecast to strike on Wednesday.
Manila, the sprawling capital of more than 12 million people lies about 100km to the south of Nock-ten's direct path, and schools were closed across the city on Wednesday as it prepared for heavy rains.
An average of 20 storms and typhoons, some of them deadly, hit the Philippines every year. Storms killed 48 people on Luzon in May and June.
Unusually heavy rains also killed 42 people last month in the country's south, an area that is normally spared typhoons and storms.