MANILA (REUTERS)- The Philippines said on Monday (Dec 19) it will not "deviate from" an international tribunal ruling that rejected China's extensive claims in the South China Sea but it must build trust with China before discussing "sensitive"bilateral issues.

China rejected the July ruling by the Permanent Court of Arbitration in the Hague after the tribunal determined that China had breached the Philippines' sovereign rights by endangering its ships and fishing and oil projects.

The ruling, on a case brought by the previous Philippine administration, soured relations with China but President Rodrigo Duterte, who took office in the Philippines on June 30, has sought to engage China, marking a reversal in the foreign policy of the old US ally.

Duterte has played down the arbitration saying, saying it would "take a back seat" during talks in China in October.

On Saturday, he said he would "set aside" the ruling and would "not impose anything on China".

Foreign Minister Perfecto Yasay issued a statement on Monday explaining that "revitalising" ties with China was one of Duterte's priorities and the government had been working to build "confidence and trust" with China.

"This we will continue to do for the foreseeable future, until such time that we achieve a trust level that will allow us to discuss the more sensitive issues in our bilateral relations," Yasay said.

The government reaffirmed "its respect for and firm adherence to this milestone ruling" and would be "guided by its parameters" when tackling the issue of maritime claims in the South China Sea, he said.

"I also wish to reiterate what the president has stated in the past that he will not deviate from the four corners of the ruling," the minister said.

Duterte said in a speech later on Monday that "some day" he would have to bring up the issue of the ruling with China but not now. Instead, he raised the possibility of sharing any resources in disputed area. "If you want, let's just develop the oil there, we can share," he said in a speech to government employees, referring to China.

Earlier, a former foreign minister, Albert del Rosario, said he was disturbed by the government's setting aside of the tribunal ruling while unwinding military dealings with the long-time ally the United States.

"The foregoing declarations are most sadly being made after we had taken a firm rules-based position to defend what is ours - and won," del Rosario said in a statement.

"Now, we seem to be on a track to relinquish those gains that have been made to benefit our people." Del Rosario was instrumental in challenging China's so-called nine-dash line on its maps, setting out its extensive South China Sea claim, and filing the case in The Hague.

Brunei, Malaysia, Taiwan and Vietnam also have claims on the waterway where about US$5 trillion (S$7.3 trillion) worth of goods passes every year.