President Rodrigo Duterte is this year's chairman of the 30th ASEAN Summit held in Manila, the Philippines' capital, on April 26-29, which mainly discussed issues in the South China Sea and the tension surrounding North Korea's nuclear program.
Former Philippine officials who dealt with the disputes say Duterte's concessions to China could weaken the ability of the Philippines and other ASEAN member states to seek Chinese compliance to the arbitration ruling and curb Beijing's increasingly assertive behavior in the disputed waters. The 72-year-old leader, however, faced calls to raise the ruling in the summit of leaders of the Association of Southeast Asian Nations that he hosted Saturday.
"It might embolden them to advance some more in their South China Sea master plan", said Golez, citing fears that China may also turn the disputed Scarborough Shoal off the northwestern Philippines into another island outpost.
The United States has criticised the construction work, warning against militarisation in the waterway where $5 trillion in annual trade passes.
"I think the Philippine government under President Duterte is pursuing what I call a cautious, pragmatic and reconciliatory approach towards the South China Sea because there is a serious intention on the part of President Duterte to really promote cooperation with China and at the same time revive friendships with our close neighbors", he said.
Aileen Baviera, an Asia studies expert at the University of Philippines Diliman, noted the ruling applied to China, and the Philippines was a party to the case.
The tribunal a year ago ruled largely in the Philippines' favour.
Since coming to power past year, Duterte has forged closer ties with China at the expense of Manila's traditional alliance with Washington.
However, a communique from the meeting of regional leaders dropped a reference to an worldwide arbitration criticising China's growing assertiveness in the South China Sea, which marks a victory for Beijing.
It also did not mention the abiding by "universally recognized principles of worldwide law, including the 1982 United Nations Convention on the Law of the Sea" that was in the draft statement. "They (China) want it further watered down", one diplomat told AFP.
One diplomat indicated that ongoing moves between China and ASEAN to draft a framework for negotiating a maritime code of conduct may have been a factor in agreeing the softened statement.
Chinese officials pressed for words that might allude to last year's worldwide arbitration ruling to be kept out of the statement, the diplomats said, particularly the term "full respect for legal and diplomatic processes".
Duterte says the ASEAN lnter-Parliamentary Assembly "plays an integral role in ensuring that the regional agreements are carried out and implemented at the national level so that the benefits of integration are felt by our people in the region".
Underlining Beijing's sensitivity about the arbitration case, the two diplomatic sources who spoke to Reuters on Saturday said Chinese embassy officials had lobbied behind the scenes for that sentence to be dropped, and saw it as a veiled reference to the ruling.
President Duterte, 2017 Asean chairman, also used the latter phrase in his address opening the summit.
The summit was also being closely watched for how Duterte, who has shocked with curse-laden tirades against the United States and other critics of his deadly drug war, handles hosting his first major diplomatic event.