A newly formed coalition of private Philippine groups, including some former government officials, plans to hold worldwide anti-China protests over the South China Sea issue on Wednesday.

The Chinese embassy's visa office in Manila will be closed on Wednesday "for security reasons", a statement on the embassy's website said.

Observers said the Philippine government, though it denies any involvement, is aiming to stir nationalism by staging anti-China protests and boost public backing for the Benigno Aquino III administration, which is facing dwindling support at home.

The protest around the Chinese consular office, located in Makati City, Manila, will be held from noon to 2 pm and is expected to draw around 5,000 people.

Similar actions outside Chinese embassies and consular offices will be held in other parts of the world, including New York, London and Rome, according to reports in Philippine media.

The rally in Manila "is going to be the start of something we intend to become bigger — not only in the Philippines, but worldwide", said Roilo Golez, former national security adviser during the term of ex-President Gloria Arroyo.

Beijing-Manila relations have been strained over overlapping claims in the South China Sea, which have led to several standoffs, including one over Huangyan Island last year, and a number of provocative statements from Manila.

A foreign ministry spokesman in Manila last week said the Philippine government has nothing to do with the long-planned protests against China, but stressed that its people have "all the right to express and voice out in a peaceful manner their positions and sentiments " on the South China Sea issue.

A similar protest outside the Chinese consulate was held in May 2012, but only drew about 200 participants, way less than the expected turnout.

Yang Baoyun, a professor on Asia-Pacific studies with Peking University, said the participation of former government officials in the protests has drawn international attention and showed the role of the government behind the scenes.

"The South China Sea issue is now the easiest card the Philippine government can play to distract its people's attention from domestic problems and improve their recognition of the administration," he said.

On Monday, Philippine President Benigno Aquino III delivered his annual State of the Nation Address, in which he spoke highly of his achievements over the past three years of his rule. Before his speech, however, thousands of protesters took to the streets in the Philippines to demand better jobs, more inclusive growth and the protection of human rights.

Ren Yuanzhe, a researcher at China Foreign Affairs University, said Manila, backed by Washington, has always been a front-runner in flaring up regional tension, adding Japanese Prime Minister Shinzo Abe's upcoming visit to the Philippines on Friday and Saturday is also a sign of support.

Manila may use the large-scale protests to garner sympathy for an international tribunal claim filed by Manila to help mediate its dispute with China, Ren said.

The Philippines last week announced that a five-member tribunal under the United Nations Convention on the Law of the Sea had convened to hear its complaints against China.

Most of the countries that have territorial disputes with China in the South China Sea, such as Vietnam, have begun to seek cooperation with China, Ren said.

"But Manila is trying to avoid addressing its problems at home by fanning nationalism with the South China Sea issue," he said.

"I believe the protests are a short-sighted move that will only hurt the Philippines' interests and regional stability."