Citing "very high risk," the Australian government advised its people not to go to Central and Western Mindanao, including the Zamboanga Peninsula, and the Sulu Archipelago and southern Sulu Sea.

The advisory, posted on the country's Department of Foreign Affairs and Trade's Smart Traveller website, said Australians who travel to the area "should typically seek professional security advice."

The advisory emphasized that regular travel insurance policies will be void in areas of concern and the government will "unlikely be able to provide consular assistance."

The advisory also pegged the official advice for the Philippines at "High degree of caution."

It said Australians travelling to the country should "pay close attention to your personal security at all times and monitor the media about possible new safety or security risks."

The Australian government also flagged an orange advice to those travelling to Eastern Mindanao, telling its citizens to "reconsider" their need to travel.

The Australian travel advice came days after US Embassy warned its citizens about "unsubstantiated yet credible" reports of kidnappings in Central Visayas and advised to "carefully consider" this when making plans to visit the region.

• READ: US Embassy issues travel warning on Central Visayas