The Philippines' airline industry is already starting to feel the effects of Monday's hostage crisis as the tourists who were planning to visit the country had canceled their flights.

Two of the country's largest airlines--flag carrier Philippine Airlines (PAL) of the Lucio Tan group of companies and Gokongwei- led Cebu Pacific--on Thursday said that the travelers are already canceling their flights and hotel room bookings.

More than 500 people from Hong Kong and other parts of China that have booked to travel to Manila in the next 30 days have canceled their flights, PAL said.

Likewise, Cebu Pacific said that rebooking and cancellation requests from about 2 percent of the company's passengers to Hong Kong have already been reported.

The tourists have canceled their trips over security concerns in the Philippines after the recent death of eight Hong Kong residents who were killed after a botched hostage rescue operation on Monday.

"PAL is beginning to feel the initial impact of a Hong Kong government advisory warning its residents to refrain from all travel to the Philippines," PAL president Jaime J. Bautista told reporters Thursday.

"Hong Kong is a very important route for PAL," Bautista said, but noted that only those coming from China have canceled their trips to the Philippines.

PAL flies to Hong Kong five times a day and corners about 6 percent of the company's revenues.

Hong Kong on Tuesday issued a warning against traveling in the Philippines at the wake of the hostage crisis.

The Philippine government had already anticipated a backlash on the country's tourism industry following the hostage crisis. Philippine President Benigno Aquino III had tasked the Department of Tourism to "re-engender the confidence of tourists" to the country.