American children's television network Nickelodeon has announced it will build an underwater resort and theme park on an island known as the Philippines' last ecological frontier, alarming environmentalists.

The firm behind SpongeBob SquarePants and Dora the Explorer said the park on Palawan island would be part of a 400-hectare (1,000-acre) undersea development showcasing the area's marine life that would give fans a chance to "interact with the brand and the iconic characters they love".

Palawan was chosen for the development because it "is known to have some of the most beautiful beaches in the world today," Ron Johnson, an executive vice president with Viacom International Media Networks, which owns Nickelodeon, said in a statement emailed to AFP on Tuesday.

Viacom's initial statement announcing the project on Monday said the resort would open in 2020 and feature restaurants and lounges six metres (20 feet) below sea level.

The development would "advocate ocean protection" and conserve coral reefs, the statement said.

But environmental group Greenpeace said it would destroy the area's world-famous marine ecosystem.

"It's sad and alarming because a theme park that big will not promote environmental protection by building those structures," Vince Cinches of Greenpeace Southeast Asia told AFP.

"Why build a viewing deck when you have the whole paradise to enjoy?"

Conservation groups call Palawan "the last frontier" because of its pristine coastlines and forests, which are among the oldest and most diverse in Southeast Asia.

Palawan is home to two UNESCO World Heritage-listed sites, a subterranean river and the Tubbataha coral reefs.

Palawan-based environmental activist Grizelda Mayo-Anda also expressed concern.

"I am wary because we have had problems already with resorts built in mangrove areas," Mayo-Anda, executive director of the Environmental Legal Assistance Center, told AFP.

"I'm really concerned because sometimes, with all due respect to the local government unit, we get captivated by new projects and we do not judiciously study the impact."

Viacom's Philippine partner, Coral World Park, insisted the resort would not hurt the environment.

"We are taking very, very careful measures to ensure that the biodiversity is kept intact," Coral World Park chairman Paul Monozca told AFP.

Coral World Park said the development would be part of a coral reef conservation programme including a marine sanctuary for species like dolphins and sea cows.

The Palawan Council for Sustainable Development, a government body, said the project had yet to be approved.

ajm/amu

VIACOM