Coast guard boats were on patrol and assault rifle-wielding police were posted at entry points to the once-pristine island that has become tainted by heavy commercialisation and overdevelopment.

Regional police head Cesar Binag said the shutdown began past midnight, with tourists barred from boarding the ferry that is the main way onto the island.

"Boracay is officially closed to tourists. We are not closing establishments but tourists cannot enter. We are implementing the instruction of the president," Binag said.

President Rodrigo Duterte ordered the shutdown this month after calling the resort a "cesspool", dirtied by tourism-related businesses flushing their raw sewage directly into the ocean.

During the closure, only residents with ID cards are allowed to board ferries to Boracay, which is home to around 40,000 people.

People on the so-called "party island" held a final bash on the beachfront on the eve of the closure, complete with a fireworks display and cheers of "Bye, Bye Boracay".

ak/ch (AFP)