A state of calamity has been declared in Isabela province, as the region is pounded by winds topping 225 kilometres an hour.
Benigno Aquino, the Philippines' president, ordered all government agencies to be on high alert to prevent casualties, while the coast guard was instructed to ban all fishing vessels from setting off to sea in the north.
Typhoon Megi is expected to head out of Luzon towards the South China Sea on Tuesday. It will grow stronger over the warm waters by Sunday, when it is expected to hit southern China, a region already plagued by floods.
Al Jazeera's Jamela Alindogan reports from Manila.
