An arbitration court hearing the dispute between China and the Philippines over the South China Sea said on Wednesday that it will deliver its decision on July 12.

China responded to the announcement by saying the tribunal in the Hague "should not have heard the case" or "issue a decision".

China has refused to be part of the arbitration since the proceedings were launched in 2013 under the United Nations Convention on the Law of the Sea (UNCLOS).

The Permanent Court of Arbitration (PCA) in the Hague made its announcement in a release posted on PCA's website.

The tribunal's decision "will first be issued via e-mail to the parties"and "there will be no in-person meeting or ceremony for the rendering of the Award," said the release.

Later on Wednesday, Foreign Ministry spokesman Hong Lei said in a written statement that the Philippines' unilateral initiation of arbitration "breaches international law”.

"The Arbitral Tribunal, established on the basis of illegal conduct and claims of the Philippines, has no jurisdiction over the relevant matters,"Hong said.

The Arbitral Tribunal "circumvented the optional exceptions declaration China has made in accordance with UNCLOS, expanded and exceeded its jurisdiction at will, and pushed forward the hearing on the relevant subject-matter”, Hong said.

"Such acts have infringed on the right of a state party to UNCLOS to choose means of dispute settlement of its own will, and undermined the integrity of the UNCLOS dispute settlement regime,"Hong added.

Earlier this month, an international group of legal experts and lawyers signed a legal opinion document questioning the tribunal's jurisdiction.