Beijing says an arbitration court hearing the dispute between China and the Philippines over the South China Sea has no jurisdiction.
Chinese Foreign Ministry spokesman, Hong Lei, said in a lengthy statement on Wednesday that Manila's unilateral lodging of the case flouted international law.
"I again stress that the arbitration court has no jurisdiction in the case and on the relevant matter, and should not hold hearings or make a ruling," the spokesman said, adding, "The Philippines' unilateral lodging of the South China Sea arbitration case is contrary to international law."
He further noted that Beijing would not accept any forced dispute resolution, saying, "On the issue of territory and disputes over maritime delineation, China does not accept any dispute resolution from a third party and does not accept any dispute resolution forced on China."
Meanwhile, China's official Xinhua news agency said in an English-language commentary that the case would only worsen the dispute.
"Manila fails to see that such an arbitration will only stir up more trouble in the South China Sea, which doesn't serve the interests of the concerned parties in the least," it said, adding that the case "even threatens to further complicate the issue by giving certain parties in the disputes the false impression they could profit by deliberately creating chaos."
A little-known international tribunal based in The Hague has said it would hand down a ruling over the South China Sea on July 12.
Experts say the ruling by the Permanent Court of Arbitration (PCA), international tribunal for the peaceful resolution of disputes between nations, risks further inflaming tensions between the Philippines and China.
In early 2013, Manila lodged the suit against Beijing contesting China's sweeping claims to most of the South China Sea. However, China has refused to participate in any hearings and says it will not comply with any decisions by the tribunal.
Beijing has long-standing disputes over maritime territory in the South China Sea with other regional states such as Brunei, Vietnam, Malaysia, the Philippines and Taiwan, which also claim territory in the region.