Philippine authorities cancelled flights and ordered thousands of people living in coastal areas to move to safer ground on Saturday as a powerful typhoon approached northeastern parts of the main island of Luzon.

With winds of up to 175 kph (109 mph), category 4 typhoon Koppu is now about 170 km (105 miles) to the northeast of Baler in Aurora province, moving west and due to make landfall on Sunday. Disaster agency officials said a few thousand people living in vulnerable coastal or low-lying areas had already sought shelter due to the risk of floods, landslides and storm surges of up to 2 metres (6.5 ft).

"We are now forcing the people to evacuate in coastal areas and river banks to minimise loss of life," Alexander Pama, executive director of the National Disaster Risk Reduction and Management Council, told a news briefing. Pama said some provincial governments had been ordered to empty coastal and low lying villages and mountain slopes due to threats of flooding, mudslides and storm surges.

"Soldiers with bull horns were going around coastal villages forcing people to flee," said a resident Vir Malabanan from Santiago, Isabela. "We've been experiencing heavy rain and strong winds for hours. We no longer have power in the province, so we rely on radio sets for news."

Rain has already reached Manila, though winds are not expected to be strong enough in the capital to cause damage. The weather bureau said ferries and fishing boats should also seek shelter or stay in port with a risk of the storm generating large sea swells. AccuWeather, a weather information provider, said Koppu could drench large areas of rice-growing Luzon with between 300 to 600 mm (12 to 24 inches) of rain and cause life-threatening flooding and mudslides.

Airport authorities have grounded 14 domestic flights, while the Coast Guard has imposed a "no sail" policy, suspending a search for a missing yacht with four on board in the South China Sea. On Friday, President Benigno Aquino appealed on television to people not to panic and to make preparations. The last time Aquino made a televised appeal was in 2013, the day before super typhoon Haiyan struck the central Philippines, killing more than 6,300 people and leaving millions homeless.

An average of 20 typhoons hit the Philippines every year.