Japan and the Philippines agreed to boost security ties in their first foreign and defense ministerial meeting on Saturday, amid worries over China's increasingly assertive maritime activities.

It was the first so-called two-plus-two talks between the two US allies, both of which have overlapping territorial claims with Beijing.

"Our two countries share serious concern about the situation in the East and South China Sea and we agreed to ensure observing international laws including the 2016 arbitral award to the Philippines" in disputes with China, as well as the UN Convention of the Law of the Sea, Japan's foreign minister Yoshimasa Hayashi said.

China claims nearly all of the South China Sea, locking it into disputes with several Southeast Asian neighbours.

In 2016, an international tribunal in The Hague invalidated China's claims in the South China Sea in a first-ever ruling. Beijing has ignored the decision.

In the meeting, "we were able to confirm our will to further enhance our collaboration in dealing with regional and global challenges and our cooperation towards the realization of the Free and Open Indo-Pacific", Hayashi said.

Areas of cooperation include ensuring safety of sea lanes in Southeast Asia and discussion towards expanding joint military drills and exchanges, among others, he said.

Defense Secretary Delfin Lorenzana echoed that, saying "we exchanged views on regional security issues of common concern, notably freedom of navigation and over flight" and "compliance with international laws" including the 2016 tribunal decision.

Besides the Philippines, Japan has formed a two-plus-two framework with eight other countries – the United States, Australia, Britain, France, Germany, India, Indonesia and Russia.