China is "laying censors and monitoring stations" inside Bajo de Masinloc, maritime law expert Jay Batongbacal said, claiming that the shoal is now turning into " rubble".

In an online forum on Tuesday, Batongbacal, director of the University of the Philippines (UP) Institute for Maritime Affairs and Law of the Sea, said according to Filipino fisherman the "laying of censors and monitoring stations" is being done by the Chinese at night.

"There could also be other activities such as laying down censors and monitoring stations that could be taking place in that area, the thing is that they are doing it at night based on the report of the fishermen in the area that I have spoken with," he said.

"That is the one that doesn't show up in the (automatic identification system) AIS. That is the one that isn't often seen on the imagery that is available to us but if were turn our attention to, trying to see what's going on at night then maybe we will have a little bit more insight into exactly what they are preparing for definitely," he added.

Batongbakal said if China succeeds ''in their plans and say in the future convert Scarborough Shoal into another military base like Fiery Cross, Subi and Mischief that would not only sent cement their illegal control but it would also have serious implications of all the rest of the region and the world."

He also reported based on some videos and statements of fishermen the Scarborough Shoal "is really turning into rubble".

"China Coast Guard force our people out and they were just trying to get shells to eat for a meal and they were force to throw them away, when you look at the video the surrounding area its really like they're in a gravel pit instead of a very rocky living reef so that's why it's troubling," said Batongbakal.

"I think that is what they are exactly doing, really trying to slowly destroy the shoal and then later on use it as an excuse to conduct what rehabilitation they will call it maybe or remediation or something like that when in truth of their doing is just basically converting a living ecosystem into another artificial island and gaslighting us and all the region along the way saying that we are the cause of the environmental destruction," he added.

National Security Council spokesman and Assistant Director General Jonathan Malaya did not confirm if the shoal has turned into rubble but he noted that the impact of China's destructive activities "has been significant in the sense that the marine environment in that area has been diminished significantly."

It is not the same as before so we are of course alarmed by that," he said.

As China continues to adhere to the Declaration on the Conduct of Parties in the South China Sea (DOC), Malaya expressed hope that China "will not" turn the shoal into an artificial island.

"The legal status of Scarborough Shoal as part of Philippine territory is clear therefore that is the red line for the Philippines. I hope that China continues to adhere to the declaration of conduct," he said.

"If you do remember the declaration of conduct (states that) no new occupation of an occupied features and we expect China to adhere to that, they always mentioned the declaration of conduct in any statement that comes out from Beijing so it is our hope that they will not go that far because reading what the president has said that would be a red line in the Philippines," he added. Robina Asido/DMS