The storm was undergoing "rapid intensification" and expected to make landfall on the sparsely populated Batanes or Babuyan islands by Tuesday afternoon, the Philippine weather agency said.

Maximum sustained winds were 185 kilometres per hour at the storm's center as of 11 am (0300 GMT), with gusts reaching up to 230 kph as it moved westward toward the archipelago nation, the weather service said.

Local officials "must waste no time in moving families out of danger zones", interior department Secretary Jonvic Remulla said in a statement.

In Taiwan, authorities said nearly 300 people will be evacuated from Hualien County in the east, adding figures could change depending on the typhoon's movement.

"We estimate that a land typhoon warning will be issued tonight... and tomorrow morning at 6 am the typhoon will approach Taiwan's offshore," the Central Weather Administration said.

Philippine weather specialist John Grender Almario told a Sunday press briefing that "severe flooding and landslides" were expected in northern areas of main island Luzon.

- Flood protests -

"We expect that the effects of the super typhoon will be felt beginning tonight," he said. "The strongest (effects) will be at 8 am tomorrow."

Strong winds and heavy rain are likely in other areas of Luzon, though Manila, where thousands turned out Sunday to protest against fraudulent flood control projects, was expected to be largely spared.

The growing corruption scandal, involving billions of dollars lost to incomplete or "ghost" flood control projects, has seen multiple lawmakers implicated and sparked national outrage.

The Philippines is the first major landmass facing the Pacific cyclone belt, and the archipelago is hit by an average of 20 storms and typhoons each year, putting millions of people in disaster-prone areas in a state of constant poverty.

Scientists warn that storms are becoming more powerful as the world warms due, in part, to the effects of human-driven climate change.

On Sunday, the Hong Kong Observatory said weather in the financial hub would "deteriorate gradually" on Tuesday and Wednesday, with gale-force winds and storm surge-driven sea levels similar to those seen in 2018's powerful Typhoon Mangkhut.