MANILA — Philippine President Rodrigo Duterte will soon meet his Chinese counterpart Xi Jinping to discuss a 2016 arbitration case over the South China Sea, his spokesman said on Tuesday, as domestic pressure grows on the firebrand leader to stand up to Beijing.

Despite his huge popularity and polls consistently delivering an approval rating of 80 percent and over, the same surveys have shown Filipinos have little trust of China and want their government to stand up to perceived maritime bullying.

Among the most contentious issues is Duterte's decision to set aside a ruling by the Permanent Court of Arbitration (PCA) in the Hague to curry favor with Beijing, in exchange for vague pledges of billion-dollar investment packages that largely have yet to materialize.

That ruling made clear numerous Philippines maritime entitlements under international law and effectively invalidated China's controversial nine-dash line claim to sovereignty over most of the South China Sea.

Presidential spokesman Salvador Panelo said he had asked Duterte whose idea it was to hold fresh talks with Xi.

"Remember that I said before that there will be a time when I will invoke that arbitral ruling?," Panelo told a regular briefing, quoting Duterte.

"'This is the time. That's why I am going there' — that's what he said," Panelo added.

He did not give a date for Duterte's trip to China but said it was likely before the end of this month.

The trip would come at a time when China is receiving international pushback over the conduct of coastguard and fishing militia in disputed areas of the South China Sea, including from U.S. Secretary of State Mike Pompeo, who last week blasted Beijing for "decades of bad behavior", in trade and at sea.

Although Duterte, who is known for scolding Western leaders, has stood by China and defended his policy of rapprochement and non-confrontation, his defense officials have spoken out.

Two diplomatic protests have been filed, the first over what the Philippines said was a recent "swarming" of more than 100 Chinese fishing boats near a tiny Philippine-occupied island.

The other was about an unannounced passage in July of five Chinese warships through the Philippines' 12-mile territorial sea, which Defense Secretary Delfin Lorenzana said was "a failure to observe protocol or common courtesy".

A Social Weather Stations poll published last month showed most Filipinos wanted the government to assert its claim to disputed islands in Spratlys and arrest Chinese fishermen caught destroying marine resources.

Panelo also said Duterte was interested in furthering discussions about jointly exploring "60-40" for offshore energy reserves inside the Philippines Exclusive Economic Zone (EEZ). — Reuters