The Philippines sought to play down simmering tensions with China on Sunday, saying Beijing was unlikely to resort to military action to resolve their maritime dispute in the South China Sea.

President Benigno Aquino dismissed as pure rhetoric recent warnings by Chinese officials of decisive action against the Philippines to reinforce Beijing's claim over the Scarborough Shoal in the South China Sea.

"We don't think that at this stage they (China) will engage in any military activities," Aquino told reporters.

"And we... have been geared towards de-escalating the situation."

He said both countries stand to lose if armed confrontation erupted over the disputed shoal, a potential Asian flashpoint where vessels from both sides were locked in a two-week stand-off that began on April 8.

China claims all of the South China Sea as a historic part of its territory, even waters close to the coasts of the Philippines and other Southeast Asian countries.

Aquino said he had issued "overriding instructions" to his military "not to escalate the issue" and dismissed Chinese warnings as "not indicative" of Beijing's "real intentions".

The Scarborough Shoal is only about 230 kilometres (140 miles) from the Philippines' main island of Luzon, while the the nearest Chinese land mass is Hainan province 1,200 kilometres to the northwest, according to naval maps.

Tensions began when Chinese maritime vessels blocked the Philippine navy from arresting the crews of eight fishing vessels which had entered the area.

Both sides accused each other of violating maritime laws, and on Saturday the Philippines alleged that a Chinese vessel veered dangerously close to its vessels in the area.

Amid the stalemate, the Philippines said it would seek more military assistance from its ally, the United States, to help it build a "credible defence posture" in securing its sovereignty.

China had earlier warned the Philippines against "internationalising" the issue, and its state media had quoted defence and military officials as saying they were prepared to fight for their territory.