Typhoon Usagi swamped rural villages in floods, knocked down power and displaced thousands more people before blowing away on Friday from the northern Philippines, which has now been pounded by five major storms in less than a month.

A new storm in the Pacific could strengthen into a powerful typhoon before hitting the Philippine archipelago on Sunday, according to state forecasters.

There were no immediate reports of casualties from the onslaught caused by Usagi, which was blowing toward southern Taiwan on Friday.

In Cagayan province in the northernmost tip of the main Luzon region, a key concrete bridge connecting two towns partly collapsed Thursday after logs swept by rampaging river currents smashed into it. Several other bridges were engulfed in floodwaters and were unusable, provincial officials said.

Usagi made landfall in the northeastern Philippines on Thursday, just two days after the last typhoon, Toraji, exited after setting off floods and forcing more than 82,500 people to flee from their homes in northern provinces.

Many of the displaced were still in emergency shelters when Usagi hit, according to welfare officials, who have scrambled to transport large numbers of food packs and other aid to more than 300 evacuation centres as the back-to-back storms and typhoons lashed the region.

The government has struggled to deal with the impact of the multiple storms, which left at least 160 people dead, displaced more than 9 million others and devastated farmland and infrastructure, mostly in Luzon.

President Ferdinand Marcos Jr's administration has spent more than 1 billion Pesos (USD 17 million) for food and other aid for hundreds of thousands of storm victims, Welfare Assistant Secretary Irene Dumlao said.

Defense Secretary Gilberto Teodoro, who oversees disaster-response efforts, sought the help of neighbouring countries, including Singapore, Indonesia, Malaysia and Brunei, in providing additional aircraft to transport food, water and other aid to villages isolated by the storms. The United States, Manila's longtime treaty ally, deployed cargo aircraft with food and other assistance.

The UN Humanitarian Country Team in the Philippines said it was raising USD 32.9 million to help the government provide assistance to about 2,10,000 people in critical need of aid and protection, especially women, children and people with disabilities, in the next three months.

“The Philippines is facing an exceptionally challenging tropical cyclone season, with successive cyclones reaching unprecedented locations and scales,” the UN team said in its emergency plan. “Local authorities, who are often impacted themselves, are overwhelmed as they simultaneously respond to the crisis and coordinate rescue efforts for affected families.”

The Philippines is battered by about 20 typhoons and tropical storms each year. It is often hit by earthquakes and has more than a dozen active volcanoes, making it one of the world's most disaster-prone countries.

In 2013, Typhoon Haiyan, one of the strongest recorded tropical cyclones, left more than 7,300 people dead or missing, flattened entire villages and caused ships to run aground and smash into houses in the central Philippines.