MANILA (REUTERS) - The deadly typhoon that killed hundreds in the Philippines also damaged dozens of homes and government infrastructure on the country's biggest, strategically most important outpost in the South China Sea, including a newly built coast guard station.

Typhoon Rai, which left nearly 400 people dead and displaced hundreds of thousands, hit the remote island of Thitu, one of nine features the Philippines occupies in the Spratly archipelago, just as it was undergoing an upgrade to facilities including the repair of a runway.

The island is located more than 483km from the Philippines.

"As soon as possible, we will rebuild the coast guard station," Philippine Coast Guard spokesman Armando Balilo told Reuters.

"We need Pagasa island, it is critical to our country," he said using the local name of the island.

Thitu's population of just 194 as of July has a strategic purpose for Manila - preserving a Philippine claim of sovereignty in the face of a resurgent China.

China claims sovereignty over the Spratlys, but Brunei, Malaysia, the Philippines, Taiwan and Vietnam all have competing claims for some or all of the islands.

Coast guard official Balilo said the island's residents were safe, and the coast guard's priority was to send relief supplies.

Images shared by the coast guard showed the trail of damage left behind by typhoon Rai on Thitu, from uprooted trees to the roofs and walls of homes being torn off.

"Only the evacuation centre was left standing, but the windows were also busted," Mr Balilo said.

Rai, which struck the Philippines last Thursday, was the strongest typhoon to hit the archipelago this year. It has affected 1.8 million and displaced 630,000 residents, the UN Office for the Coordination of Humanitarian Affairs said.

It revived memories in the Philippines of the devastation brought in 2013 by Typhoon Haiyan, one of the most powerful tropical cyclones ever recorded, which killed 6,300.

Mr Balilo said the coast guard managed to reach Dinagat island, one of the south-eastern provinces first pounded by the typhoon, on Tuesday to deliver desperately needed relief supplies after residents had been pleading for food, water and shelter.