MANILA - FIVE air traffic controllers who were late or absent from work a day after Christmas were suspended after two flights were forced to circle a southern airport because no one was manning the control tower, Philippine civil aviation officials said on Saturday.

A Philippine Airlines jet from Manila with 156 passengers arrived early on Friday morning at Zamboanga city's airport but was forced to circle for nearly 30 minutes before being allowed to land, Ramon Atilano, PAL's Zamboanga manager, told The Associated Press.

A smaller, Cebu Pacific airline turbo plane from Cebu city that arrived minutes ahead of the PAL flight had to land on its own, Zamboanga airport manager Celso Bayabos said. Bayabos said the tower was not manned for 40 minutes.

The Civil Aviation Authority of the Philippines said it has suspended five controllers and ordered an investigation into the incident. Those found liable could face administrative sanctions, it added.

It was unclear if they also could face criminal charges.

The Zamboanga city airport is miles 900 kilometres south of Manila.

Mr Bayabos said two of the controllers were absent without notice on Friday, two came in late, and one had filed a leave approved by her supervisor, but the notice did not reach the airport administration office.

The tardy air controllers explained they had difficulty getting a ride to work because public transportation was scarce the day after Christmas. But Mr Bayabos said they were apparently still in holiday mode.

'They got their bonus before Dec 24 and it was possible that they were enjoying their Christmas celebration with their families,' he added.

The Philippines, which is more than 80 per cent Roman Catholic, has an official holiday from Dec 25 to Jan 2. -- AP