The Philippine Ports Authority on Tuesday urged shipping lines to add more vessels to serve the estimated 5.1 million holiday travelers expected to pass through the country's various seaports. 

The influx of passengers is expected from 16 December to 15 January next year, said PPA general manager, Atty. Jay Daniel Santiago. The PPA said 4.7 million passengers utilized the country's ports in the same period last year.

Santiago said the Port of Batangas will be the busiest, and contingency measures have been readied to prevent passenger congestion.

"The real challenge here is the number of passengers arriving. I have been inspecting our ports, and the Port of Batangas sometimes becomes a sea of humanity on the eve of the holiday break," he said. "You cannot even see the concrete, all you see are the people."