MANILA - Acting Chief Justice Antonio Carpio found President Rodrigo Duterte's remarks on defending the country's interests in the West Philippine Sea vis-a-vis China wanting.

Carpio said Duterte had "the correct position" but should have elaborated on how he would defend the Philippines' interest in the disputed sea.

"Well that's the correct position. We should never give up our rights there," Carpio told reporters after the President's third State of the Nation Address.

"Well, I was hoping that he would elaborate on how we will protect our sovereign rights in the West Philippine Sea. Because I think everybody agrees we have to protect our sovereign rights. It's really how?"

Duterte, in his speech, said he would not waver in defending the Philippines' interests, despite seeking closer ties with Beijing.

• Duterte says to 'defend' Philippine interests in South China Sea

"Our improved relationship with China does not mean we will waver to defend our interest in the West Philippine Sea," Duterte said.

“Opening lines of communication and amicably managing differences have led to positive developments that include renewed access of Filipino fishermen in the areas in dispute in the Philippines—West Philippine Sea."

Carpio, meanwhile, urged the Department of Foreign Affairs to publicize what kind of protests it has filed against China.

In May, the government said it has taken "diplomatic actions" against China over its activities in the West Philippine Sea, including within the country's exclusive economic zone or EEZ.

• Philippines taking 'diplomatic actions' vs China over South China Sea activities

Carpio cited the government's refusal to confront China over Sandy Cay, a geological feature near the Philippine-held Pag-asa Island (Thitu Island) in the West Philippine Sea.

• Duterte won’t fight China over Sandy Cay

"It would, of course, be helpful if the DFA will tell us exactly what kind of protest they filed and when and over what. Because for example, Sandy Cay, China seized Sandy Cay from us last year and the DFA Secretary said we will not protest," he said.

"Since he said that, then we know there was no protest over the seizure of Sandy Cay. And that is one of the most important developments recently."

Last month, Magdalo party-list Rep. Gary Alejano challenged Foreign Affairs Secretary Alan Peter Cayetano to prove that the Philippines is still in control of Sandy Cay.

The opposition lawmaker said he received information from a well-placed source that Duterte had ordered the military to stop the patrols in the West Philippine Sea.

• Prove me wrong: Alejano to Cayetano over Sandy Cay
• No Duterte order to stop patrols in South China Sea - aide

Cayetano called the lawmaker a liar and offered him to be escorted to Sandy Cay. --With a report from Ina Reformina, ABS-CBN News