A slow-moving typhoon spawning torrential rains slammed into eastern Taiwan early Thursday, flooding farmlands, disrupting transportation and turning the normally bustling capital of Taipei into a ghost town.

Typhoon Saola, which killed at least 23 people in the Philippines, has already been blamed for four deaths in Taiwan, with the toll expected to rise.

The storm made landfall near the eastern coastal city of Hualien just before daybreak, before veering northward and hugging the coast. It was expected to pass near the northern port city of Keelung and skirt the Taipei suburbs by midday.

Packing sustained winds of 118 km/h and gusts of 155 km/h, Saola's slow speed -- only 12 km/h -- made it a virtual certainty that the heavy rains inundating northern Taiwan for the past 48 hours would continue through the weekend. That raised the prospect of potentially devastating flooding in areas that have already absorbed more than 1,000 millimeters of rain since Tuesday.

Authorities ordered offices and businesses closed throughout northern Taiwan, including in Taipei. Normally busy streets in the capital were deserted during the morning rush hour, as cleanup crews laboured to clear them of hundreds of trees and branches felled during the night by Saola's ferocious approach.

Television footage showed hectare upon hectare of flooded farmland in low-lying coastal areas, punctuated by scenes of raging rivers and roads blocked by mudslides in the island's mountainous centre.

The Defence Ministry mobilized 48,000 soldiers to help mitigate the storm's impact, dispatching many to help hard-pressed farmers try to save threatened fruit and vegetable harvests.

Dozens of flights were cancelled at Taipei's main international airport, and rail transport throughout the island was disrupted.

The typhoon left at least 14 people dead in the Philippines earlier this week and caused 154,000 to flee their homes.

Fierce rain and winds, compounded by a high tide, swamped a boulevard in the Philippine capital with garbage-laden water from Manila Bay and forced the U.S. Embassy to close Wednesday. Manila schools were also closed due to sporadic flooding and strong winds.