The Philippine foreign secretary on Sunday called on other nations to take a stand on China's new aggressiveness in a simmering territorial dispute over a shoal in the South China Sea.

Albert del Rosario warned in a statement that other nations would be affected by China's claim over the mineral-rich area if they did not speak up now, like the Philippines is doing.

"Since the freedom of navigation and unimpeded commerce in the (South China Sea) are of great import to many nations, all should consider what China is endeavouring to do in the Scarborough Shoal," del Rosario said.

"All, not just the Philippines will be ultimately negatively affected if we do not take a stand," he said in an SMS message sent to reporters.

He added that China's efforts to claim the entire South China Sea as its territory was "clearly baseless."

The statement came amid increased tensions after China deployed ships near the Scarborough Shoal, an outcropping in the South China Sea just about 230 kilometres (140 miles) from the Philippines' main island of Luzon.

The nearest Chinese land mass from Scarborough Shoal is Hainan province, 1,200 kilometres, (750 miles) to the northwest, according to Philippine naval maps given to the media.

China claims all of the South China Sea as its own on historical grounds, even waters approaching the coasts of the Philippines and other Southeast Asian countries.

The rival claims have been a source of regional tensions for decades, and the Philippines as well as Vietnam have accused China over the past year of becoming increasingly aggressive in asserting its position.

The latest flare-up occurred on April 8 when the Philippines found the eight Chinese fishing boats at Scarborough Shoal, and sent its warship to arrest the crew.

China quickly deployed three civilian maritime vessels that took turns in blocking the warship.

In a bid to calm the situation, the Philippines pulled back its warship and replaced it with a coast guard vessel and the fishing vessels later sailed away.

However China has refused to withdraw its ships unless the Philippine coast guard vessel retreats first. Two Chinese fisheries ships are now in a standoff with a lone Philippine coast guard vessel at the shoal.

The Philippines has been actively urging its fellow members of the Association of Southeast Asian Nations to take a firmer stance on China's claim over the South China Sea.