Foreign donations also poured in to boost local efforts to deliver help to the central and southern provinces battered by Typhoon Rai, ahead of Christmas, presidential spokesman Karlo Nograles said.
Duterte announced the declaration of a state of calamity during a televised talk on Monday evening, Nograles said.
"The declaration of a state of calamity will hasten the rescue and relief and rehabilitation efforts of the government and the private sector," Duterte said.
"This will also be an effective mechanism to control the prices of goods and commodities in the areas," he added.
At least 375 people were killed in floods, landslides and other accidents caused by the typhoon, police said.
About 2.4 million people were affected by Rai's onslaught, including some 684,000 people who were displaced, according to the United Nations Office for the Coordination of Humanitarian Affairs.
China on Wednesday announced it was donating 1 million dollars to relief efforts, while the European Union said it was allocating an initial amount of 1.7 million euros in humanitarian assistance.
The United States, France, Canada, Australia, Japan, Britain and other countries have also sent and pledged assistance, Nograles said.
Typhoon Rai, which slammed into the country's eastern coast on December 16, flattened thousands of houses, ripped off rooftops, damaged buildings, uprooted trees and knocked out power and communication lines.
