Typhoon Bopha has made landfall over Baganga in the southern Philippines, carrying winds of up to 160 kilometres an hour.
The weather system is forecast to move west at 26 km/h through the major southern island of Mindanao.
More than 40,000 people have crammed into emergency shelters, and there are reports from the south of widespread power blackouts and waist-high floods in some low-lying areas.
Dozens of flights have been cancelled and ships have been ordered to stay in port.
Many people moved out of the area before the arrival of the storm - the strongest this year for the Philippines.
Fernando Cada from the Philippine weather forecasting agency PA-GASA's described the conditions for Radio Australia's Connect Asia.
"It is concentrated in northern Mindinao, and some areas of Visayas, and still the maximum sustained wind is almost the same as last night - 175 kilometre per hour near the centre and the gustiness is around 210 kilometre per hour.
"It's already made landfall around 4am this morning Philippine time, near the area of near the area of Baganga Davao Oriental."
President Benigno Aquino said authorities have been stockpiling food supplies and rescue equipment, and Gwendolyn Pang, the Red Cross spokeswoman for the Philippines, told Radio Australia they have been preparing their equipment and staff since Saturday.
Military and coast guard personnel deployed in vulnerable areas amid fears the typhoon could trigger landslides and floods.
Trail of destruction
Yesterday, Palau narrowly escaped a direct hit from Typhoon Bopha, but strong winds caused flooding in some of the outlying coastal villages and around the islands of Angaur and Peleliu.
President Johnson Toribiong is waiting for damage assessments before possibly declaring a disaster.
Greg Grimsich from the United Nations Office for the Coordination of Humanitarian Affairs told Radio Australia that international aid groups are on standby to help if required.
"The damage is less than expected but it still remains significant for people that were there," he said.