Outbound passengers on all international flights must "add 30 minutes for them to be able to catch their flights," Manila International Airport Authority General Manager Edgar Manda said in a radio broadcast.
"The usual three-hour (check-in requirement) will be adjusted to three-and-a-half hours," he said. "The security checks will be twice as strict as before."
Washington on Monday issued an emergency directive asking all foreign carriers to place armed sky marshals on flights deemed by US officials to be at risk of possible terror attack.
In the past two weeks, seven US-bound flights have been cancelled and others escorted to US airports by F-16 jets amid fears of a terrorist attack.
On Friday, President Arroyo said her administration was "prepared to deploy air marshals on PAL (Philippine Airlines) planes entering US territory as requested."
Col. Andres Caro, head of the Philippine National Police-Aviation Security Group, said the Philippines has "trained officers to do this job but we are waiting for the go-signal from Malacanang."
PAL spokesman Rolando Estabillo, whose flag carrier flies thrice daily to the US West Coast and once a week to Canada, declined to comment.
"We can’t comment on it yet until we get official communication," he told reporters.
Manda said there was a heavy crush of departing passengers at the international terminal after the Christmas holidays. More than seven million Filipinos live or work abroad. — AFP, Rudy Santos