The Philippines said Wednesday it was on "the right track" in seeking to have a UN tribunal strike down China's claims to most of the South China Sea, after the Chinese government rejected the process.
President Benigno Aquino's chief aide, Rene Almendras, said the government expected China to ignore the plan to bring the matter up at the United Nations and stressed the case could still proceed without Beijing' approval.
"We will follow the process whether they agree to it or not," Alemndras told reporters.
"Of course, we are of the opinion that we are on the right track... we would not have started it if we did not think that we would have enough basis to file all these issuances."
The Philippines announced last month it had applied for its dispute with China over the South China Sea to be arbitrated under the United Nations Convention on the Law of the Sea, a 1982 treaty signed by both countries.
The Philippines wants the tribunal to declare Chinese claims to most of the sea, which is believed to sit atop vast natural resources and is home to rich fishing grounds, as unlawful.
But China says it has sovereign rights over nearly all of the South China Sea, even waters approaching the coasts of the Philippines and other Southeast Asian nations.
On Tuesday China announced it had rejected the Philippines' call for UN arbitration, insisting on bilateral negotiations with its less powerful neighbour.
Although China has recently sent ships into the South China Sea to enforce its claims and established a local government to rule over the contested waters, it warned the Philippines not to increase tensions.
"The Philippine side (should) keep its word not to take any action that magnifies and complicates the issue," foreign ministry spokesman Hong Lei told reporters in Beijing.
Under the UN convention's rules, the arbitration can proceed even if China declines to participate.
China can choose to ignore any eventual ruling by the tribunal. Nevertheless, a UN verdict that its claims were unlawful would be a diplomatic blow.