MANILA: The Philippines will take "all appropriate actions to cause the removal of barriers" in a disputed area of the South China Sea, the country's national security advisor said on Monday.

The Philippines on Sunday shared images of a floating barrier blocking fishing vessel access in the Scarborough Shoal with Chinese coast guard ships nearby, and said it would protect the rights of its fishermen.

"We condemn the installation of floating barriers by the Chinese coast guard," national security advisor Eduardo Año said in a statement.

"The placement by the People's Republic of China of a barrier violates the traditional fishing rights of our fishermen," he added.

The country's foreign ministry on Monday said that the barriers were a violation of international law and that the Philippines would "take all appropriate measures to protect our country's sovereignty and the livelihood of our fisherfolk".

The Chinese embassy in Manila did not respond to requests for comment.

China claims 90% of the South China Sea, overlapping with the exclusive economic zones of Vietnam, Malaysia, Brunei, Indonesia and the Philippines. Beijing seized the Scarborough Shoal in 2012 and forced fishermen from the Philippines to travel further for smaller catches.

Philippine coast guard and fisheries bureau personnel discovered the floating barrier, estimated at 300 m (1,000 feet) long, on a routine patrol on Friday near the shoal, locally known as Bajo de Masinloc, according to Commodore Jay Tarriela, a coast guard spokesperson.

"We have to be very careful (not to commit) any diplomatic misstep," Tarriela said in a radio interview on Monday before the government's comments, when asked whether the coast guard was planning to remove the barrier.

Tarriela said that according to Filipino fishermen, the Chinese coast guard usually installs such barriers when they monitor a large number of fishermen in the area, then remove it later.