Planes operating at the Philippines' main airport are facing a growing danger from waterbirds descending there after losing nearby swamps to development, authorities said Monday.

Airlines complained last month to the Manila International Airport Authority about the worsening problem of birds flying into planes, Alex Cariaga, head of the airport's ground operations safety division.

He said the Airline Operators Council, a group representing all carriers that serve Manila airport, said there had been 23 incidents in which birds were sucked up into jet engines last year.

The so-called "bird strikes", which could cause a plane to crash, was up from just nine in 2009, Cariaga told AFP.

However there had been no major incident yet due to the bird strikes.

Cariaga said the problem appeared to worsen after developers reclaimed some small lagoons near the airport runway last year to build warehouses.

"We thought it was a good thing because we expected the birds to move elsewhere," he said.

However the birds, mainly egrets, instead moved to the grassy areas beside the runway to hunt frogs, grasshoppers, lizards and other prey.

Cariaga said pilots frequently contacted the control tower for help whenever they saw birds wandering onto the runway.

He said the airport's 15-member ground safety team has to then scramble to the runway with noisemaking equipment to scare off the birds.

The Philippines is a key pit-stop on the East Asian-Australasian flyway, in which enormous numbers of birds fly between the northern and southern hemispheres to escape cold weather.

Apart from the migratory birds, Cariaga said the team also had to deal with domesticated pigeons that were raised by surrounding communities.

"These pigeons would descend in large flocks. We have asked the local governments to discourage residents from raising birds, but truth to tell, there is no ordinance right now that bans the practice," he said.