The lighthouse on Zhubi Reef of Nansha Islands in the South China Sea is in use on April 5, 2016. [Photo/Xinhua]

Experts in international law from around the world have urged the Philippines to return to the negotiating table with China to solve the South China Sea issue in a reasoned and peaceful manner.

They spoke after a weekend seminar found that any verdict delivered by an arbitration tribunal based in The Hague will have no legal validity because China and the Philippines have not reached any agreement to authorize it to intervene in the dispute.

The arbitral tribunal under the auspices of the Permanent Court of Arbitration in The Hague is thought to be close to issuing a ruling on arbitration launched unilaterally by Manila.

The tribunal has been established under appendix VII of the United Nations Convention on the Law of the Sea.

The experts, some of whom helped draft the Convention, discussed the case at a seminar on South China Sea Arbitration and International Rule of Law. It was organized by Leiden University's Grotius Center for International Legal Studies and Wuhan University's Institute of Boundary and Ocean Studies.

The experts said the court has no jurisdiction over a sovereignty dispute under the framework of the Convention.

"China has taken the right stance of nonparticipation and nonacceptance in the dispute arbitration, which has been stirred up mainly due to the geopolitical strategy of another power in the region," said Abdul Koroma, former judge of the International Court of Justice, the principal judicial organ of the United Nations based in The Hague.

Koroma, a former Sierra Leone ambassador to the United Nations and the European Union, said the court had not obtained agreement from the parties concerned to conduct the arbitration, which is a required precondition under United Nations law.

He said that only the Philippines has filed the arbitration case, meaning that it is one-sided and that the authority required to accord with international law is lacking.