No obligation

Since China refused to bring the disputes to the international tribunal, some media reports have interpreted Beijing's response as a fear to lose the case.

Yi Ping, a lecturer at the School of Law of Peking University, said Beijing has no obligation to accept the invitation.

As early as 2006, the Chinese government submitted a written statement to the UN, making it clear that China does not accept international arbitration "as described in section 2 of part XV of UNCLOS in disputes ... concerning maritime delimitation, territory and military activities," he said in an article published by the China News Agency on April 27.

By that time, Beijing had already asserted its claims to Huangyan Island in the South China Sea, which means even if the Philippines does bring the case to the ITLOS, China is not obliged to appear in the tribunal, he said.

Tiglao put forward a similar argument, speaking of China's declaration following the ratification of the convention.

"The People's Republic of China reaffirms its sovereignty over all its archipelagos and islands as listed in article 2 of the Law of the People's Republic of China on the territorial sea and the contiguous zone, which was promulgated on Feb. 25, 1992," the document reads.

"That law declared as part of China what it called the Zhongsha Islands, which included Huangyan (Panatag to us)," Tiglao said.

Meanwhile, a brief glimpse of 19 cases submitted to the Tribunal since 1997 showed that maritime disputes, rather than territorial ones, fall within the competence of the organization, he added.

True motives

The Philippines said it would go it alone if Beijing insisted on turning down its invitation.

The paradox that Manila is seeking a solution which it had declared earlier it would not recognize raised questions about the true motives behind its aggressive push.

"He (Aquino) insists that the dispute be decided by a court which, however, can't have jurisdiction over it. This President is making us the laughing stock of the world," Tiglao said.

The hardball tactics, Yi said, aimed to complicate the situation instead of appease it.

"The Philippine government, fully aware of the consistent position of the Chinese government, still had its own way to push forward the invitation," he said.

"The purpose is nothing but to discredit the Chinese government as ignoring the international judicial system and rejecting dispute settlement through legal means," he added.