Five Philippine legislators say they will visit a disputed island in the South China Sea Wednesday to reinforce their country's claims in the area.

The island is in the potentially oil- and gas-rich Spratly Islands, which are claimed in whole or part by six governments. Both Vietnam and the Philippines have complained of Chinese naval vessels interfering with oil exploration in waters near the islands.

The five legislators, who are affiliated with President Benigno Aquino, said Monday they will also gather data for laws to build up the Philippines' defenses in the area. Organizer Walden Bello said they will also look for ways to expand sustainable economic activities in the area.

Bello described the trip as a “peace and sovereignty mission” to support Philippine claims in what the country has begun calling the West Philippine Sea.

Vietnam, the Philippines, Malaysia and Brunei all claim 370-kilometer exclusive economic zones, which extend into parts of the Spratly chain. China and Taiwan claim the entire chain based in part on a centuries-old Chinese map.

The issue is expected to be discussed at this week's meeting of the Association of Southeast Asian Nations in Bali, which will be under way when the legislators' trip takes place.