Last year's host, Emmy Award winner Steve Harvey - who shot to notoriety for initially announcing the wrong winner - returns for this year's three-hour pageant that starts at 8:00 am (local time) in Manila.
Latin American beauties led by Miss Colombia Andrea Tovar and Miss Peru's Valeria Piazza were the odds-on favourites for the crown according to online betting sites.
Marina Jacoby, only the second black woman to be crowned Miss Brazil, is also touted as a possible winner.
Beauty contests are phenomenally popular in the Philippines, and the pageant will be broadcast live across the country.
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But President Rodrigo Duterte's government rejected popular calls to declare a national holiday for the event.
Today's show is to be headlined by US performers including Grammy award-winning rhythm and blues group Boyz II Men and rapper and Grammy award nominee Flo Rida.
Pia Wurtzbach of the Philippines currently holds the crown, following a comical error in which host Harvey mistakenly awarded the title to Miss Colombia.
The Philippine tourism ministry on Saturday reached out to the American actor-comedian, saying he has "millions of excited fans in the Philippines who look forward to having him".
Manila agreed to host the pageant as part of efforts to draw tourists and investors to the developing Asian nation's high-flying economy, now one of the fastest-growing in Asia.
"We... Throw our support for the Miss Philippines candidate Maxine Medina who deserves all the moral boost she can get for working very hard and giving her best in a competition that promotes goodwill and friendship among nations," Duterte's spokesman Ernesto Abella said.
And last month environmentalists hit out at pageant organisers for letting the bikini-clad contestants swim with endangered whale sharks.