From Australian Government website:
Many international and domestic flights through Manila’s Ninoy Aquino International Airport (NAIA) with Philippine Airlines and Cebu Pacific have been cancelled or re-scheduled due to airport maintenance between 6-11 March 2017. Contact your airline or tour operator for information on possible disruptions (see Local travel). The level of this advice has not changed. We continue to advise you to exercise a high degree of caution in the Philippines overall. Higher levels apply in some parts of the country.