It was the biggest rise since March 2011, when imports grew by 21.9%, National Statistics Office figures showed.
The Philippines, formerly an economic laggard, grew by a remarkable 7.2% in 2013 despite a series of disasters including the devastating Super Typhoon Haiyan in November. Its growth last year was second in Asia only to China, officials said.
Imports surged due to a recovery in Philippine exports such as electronics and garments and increased spending on infrastructure, especially in areas affected by Haiyan, said Rosemarie Edillon, assistant director general of the government's socio-economic planning agency.
"The economy is definitely going to grow. A huge chunk of these imports are for production: capital goods and investments for the manufacture of other goods," she told AFP.
Imported raw materials are a major input in many of the country's key exports such as electronics and garments so the surging imports mean even higher exports later, she said.
"These imports are a leading indicator for exports two or three months down the road. If imports in January increase, we will probably see an increase in exports in March and April," she said.
The increase in shipments of steel, metal and chemical products were also an indication of the major construction efforts being undertaken, both to upgrade infrastructure and to rebuild the damage caused by the disasters, she added.
Imports in January hit US$5.75 billion (184 billion baht), up 21.8% from the same period last year, the statistics office said.
This resulted in a trade deficit of $1.37 billion in January, up 92% from the same period in 2013.
Socio-economic Planning Secretary Arsenio Balisacan also said in a statement that "this positive (import) performance may be reflective of the optimistic outlook of businesses on their own operations", in the second quarter of the year.
China was the biggest source of imports to the Philippines, accounting for 14.7% of the total, with the United States in second with 10.6%, the statistics office added.