Tropical storm Mirinae struck Vietnam's central coast Monday, unleashing heavy rains and winds and forcing more than 80,000 people to evacuate.

The storm packed winds of more than 100 km/h as it made landfall in Phu Yen province Monday afternoon.

Mirinae hit the Philippines with typhoon strength over the weekend. It killed 20 people before losing intensity as it moved across the South China Sea toward Vietnam.

Heavy rains lashed Binh Dinh and Phu Yen provinces as the storm made landfall in Vietnam, but no deaths were reported.

Both Vietnam and the Philippines are still recovering from Typhoon Ketsana, which brought the Philippine capital, Manila, its worst flooding in 40 years when it struck in September. Ketsana killed 160 people in Vietnam.

In the Philippines, Ketsana and two later storms killed more than 900. Some 87,000 people who fled the storms were still living in temporary shelters when Mirinae struck.

The latest typhoon left 20 dead, mostly from drowning, in six provinces. Four people were missing, disaster response officials said.

Forecasters said they were watching a low pressure area about 300 kilometres off the eastern coast of the northern Philippines, which along with northeastern monsoon winds, could bring rain and gale-force winds to the mountainous region.

Strong winds and huge waves destroyed three fishing boats and overturned about a dozen others off northern Cagayan province early Monday, tossing 39 fishermen into the rough sea, Cagayan disaster official Bonifacio Cuarteros said.

Most of the fishermen swam back to shore or were rescued by fellow fishermen. One remained missing, Cuarteros said.