The Philippines will limit the number of visitors setting foot on its most treasured island resort each day when it reopens to tourists on October 26 after a six-month rehabilitation effort, an environment official said on Wednesday.

Boracay, located off the northern tip of the central island of Panay, is famed for its sugary white sands, turquoise waters, lively nightlife and abundant water sports, which attracted nearly 2 million domestic and foreign visitors last year.

But in April, President Rodrigo Duterte ordered the closure of the island, calling it a "cesspool", because of sewage dumped into the sea and buildings constructed too close to the shore.

About a third of the 600 to 700 resorts on Boracay, about 308 km (192 miles) from Manila, the capital, were operating without permits, authorities found.

Just 19,000 tourists will be allowed on the island on any given day, with the number of workers capped at 15,000 daily, the environment official, Sherwin Rigor, said in a television interview.

Only half of the island's 12,000 existing hotel rooms will be allowed to open each day, he added, to ensure the number of guests on the tiny 10-sq-km (4-sq-mile) island is below its "carrying capacity" of 55,000.

Rigor, who is an undersecretary at the Department of Environment and Natural Resources, added that authorities would ban beachfront parties, and activities such as eating, smoking and drinking there.

The closure of Boracay, which earns the Philippines more than a billion dollars in tourism revenue every year, weighed on gross domestic product in the second quarter. Growth slowed to a near three-year low of 6 percent in April-June.