BORACAY, Aklan -- Southeast Asian diplomats began Sunday top-level discussions here on a code of conduct framework that regional leaders hope to finish this year to help de-escalate tensions in the South China Sea.

A framework and later a legally binding code could serve as President Rodrigo Duterte's "legacy" as this year's chairman of the Association of Southeast Asian Nations (ASEAN), said former National Security Adviser Roilo Golez.

The framework has been in the works for years since China and the regional bloc agreed in a 2002 declaration to "undertake self-restraint" and "refrain" from occupying islands and other features in the dispute areas.

"There's still a long way to go but ASEAN is really working hard to have this code of conduct concluded very soon," Philippine foreign affairs spokesman Charles Jose told reporters here.

Golez said a code of conduct "has become virtually moot and academic," citing China's construction of artificial islands and installation of weapons on them while discussing the document with ASEAN.

"I expect China to still resist the finalization and approval so that China can further militarize the artificial islands with the placement of offensive medium-range and long-range missiles," he told ABS-CBN News.

But Jose said a code of conduct would still be "useful... in regulating future behavior of parties concerned."

"It's in everyone's interest to have a code of conduct for maintaining peace and security and managing tensions in the area," he said.

Maritime law professor Jay Batongbacal played down the code of conduct framework, likening it to "having a table of contents without the rest of the book."

"So even if they say that 'militarization' (of disputed islands) will be included, without substantial agreements, it will be practically useless because by the time they do discuss substance, the militarization may already be complete," he told ABS-CBN News.

Foreign Secretary Perfecto Yasay Jr. earlier said the Philippines would not discuss its arbitral victory that junked China's sweeping claims over the vast waterway.

Under Duterte, the Philippines has realigned with Beijing, which promised around $24 billion in investments development aid during his state visit to China last year.

"The question is: are the economic benefits an equitable trade-off compared to jeopardizing our position on the West Philippine Sea?" Golez said.