The Philippines and China have reached a "friendly" understanding allowing Filipinos to fish around a disputed shoal seized by Beijing in 2012, a senior aide to President Rodrigo Duterte said Monday.

Duterte negotiated the understanding during his recent meeting in Beijing with Chinese President Xi Jinping, said Manila's national security adviser Hermogenes Esperon.

As a result, he said, in recent days Filipino fishermen have been able to fish unmolested at Scarborough Shoal in the South China Sea while Chinese government vessels have patrolled nearby.

"There is no agreement... but our president believes that our fishermen will no longer be harassed because he already brought up this matter" during his visit to China, Esperon told the media.

"The coastguard of China is there, but their navy is gone. And now, our fishermen are no longer being accosted, no longer being forced out, so we can say things are now friendly," he added.

China took control of Scarborough Shoal, 230 kilometres (140 miles) west of the main Philippine island of Luzon, in 2012. It had been driving away Filipino fishermen from the rich fishing ground, sometimes using water cannon.

But last weekend Filipino fishermen were once more able to fish at the shoal with the Chinese ships not interfering.

Esperon stressed that neither country dropped its claim to the shoal, with China insisting on its "historical rights".

China claims most of the South China Sea, home to vital shipping lanes and rich fishing grounds, despite partial counter-claims by the Philippines, Brunei, Malaysia, Taiwan and Vietnam.

Esperon said Duterte's position was that the Philippines also had "historical rights," and that it was also bolstered by an international tribunal ruling in July that there was no basis for China's claims to most of the South China Sea.

He said the two leaders decided to sidestep the issue to repair frayed ties.

"There is no talk on territorial rights, there is no talk on assertion of rights, but they respect our traditional rights," Esperon added.

Duterte's predecessor, then-president Benigno Aquino, had brought the case before the international tribunal which resulted in the resounding victory over China.

Aquino's strong opposition to China's territorial claims strained ties with Beijing.

However Duterte, who was elected in May, has said he will not press the territorial issue and instead seek more aid and investment from China.

"There is no resolution, so why allow yourselves to be in that confrontational position when you can talk about economic relations, trade relations?" said Esperon.

"It is win-win for both but this is not to say that we have dropped our claim."