Part of a ceiling collapsed in the Philippines' biggest airport Thursday, slightly injuring a foreign passenger, the latest in a series of incidents at a facility seen as among the worst in the world.

The collapse at a restaurant at Terminal 3 of Manila airport "slightly scratched" a male foreign passenger, according to airport spokesman David de Castro.

He was treated for the injury but insisted on leaving on his flight for Japan hours later, de Castro told AFP, declining to give more information on the passenger.

De Castro said the collapse did not involve the building's concrete ceiling but rather a facade on which the restaurant had affixed overhead lights.

"They are allowed to make their own construction inside these restaurants," he said, adding that airport authorities would investigate if substandard materials were used.

Terminal 3 opened in 2008 after a years-long legal row between the government and the Filipino-German consortium that built it, with the authorities citing breach of contract and a failure to conform with safety standards.

Designed to handle 13 million passengers annually, it was built to decongest the capital's older terminals.

While Terminal 3 has not suffered any major incidents since it underwent a major rehabilitation in 2013-14, according to de Castro, Manila airport's 34-year-old Terminal 1 has a much more unfavourable reputation.

Passengers have complained of leaking ceilings, collapsed floors, malfunctioning equipment, congestion, dilapidated facilities and rude or corrupt personnel.

It led to Manila topping a list of the world's worst airports compiled by the travel website "The Guide to Sleeping in Airports" from 2011-13.

However it has since improved its standing, and is no longer listed as the worst, partly due to decongestion as more passengers have begun travelling through Terminal 3.