Top diplomats from Japan, the US, Australia and India have compiled a set of measures to reinforce maritime safety and cybersecurity and to support other Asia-Pacific countries in improving their defences during growing tensions in the regional seas.

After the meeting in Tokyo, Japanese foreign minister Yoko Kamikawa, US secretary of state Antony Blinken, Australian foreign minister Penny Wong and Indian external affairs minister Subrahmayam Jaishankar said they were “seriously concerned” about the tensions and expressed “strong opposition” to unilateral changes to the status quo by coercion.

They noted “the militarisation of disputed features, and coercive and intimidating manoeuvres in the South China Sea” as examples, but carefully avoided identifying China in their joint statement.

Several regional governments dispute China’s sweeping territorial claims over the South China Sea, which has crucial maritime trade routes and potential energy reserves. It also claims self-governing Taiwan as its territory, to be annexed by force if necessary.

At what are known as the Quad talks, the four ministers agreed on a number of initiatives to counter cyber attacks, ensure maritime security and deal with disinformation.

They also announced expanded support for other countries, including in south-east Asia and Pacific islands, to bolster their abilities in those areas as the Quad seek to expand its partnerships.

The ministers plan to launch a maritime legal dialogue to focus on the international law of the sea.

They said they were determined to contribute to maintaining and developing free-and-open maritime order consistent with the UN Convention on the Law of the Sea in the Indian and the Pacific Oceans and to enhance cooperation and coordination on it.

Their initiatives included support for installing a secure telecommunications network in Palau and building cybersecurity capacity in the Philippines and India, according to the joint statement.

The ministers reaffirmed their commitment to improving the region’s connectivity through the development of resilient infrastructure such as undersea cables.

Mr Blinken sits with Australian foreign minister Penny Wong
The ministers did not explicitly mention China (AP)

Mr Blinken told a joint news conference: “We are committed to putting our collective resources, our collective strength to work to benefit people across the region that we share.

“We continue to work with partners to ensure that freedom of navigation, overflight, the unimpeded flow of lawful maritime commerce that these continue to go forward. They are critical to the region’s security. They’re critical to its ongoing prosperity.”

Ms Kamikawa said maritime security in the region is increasingly unstable, so unity and cooperation were needed more than ever among the Quad countries in securing a rules-based free and open international order.

Without naming China, talks host Ms Kamikawa said escalating tensions in “a certain region” and cyber attacks by “a certain country” could easily spill to other countries and increase their risks.

Japanese foreign minister Yoko Kamikawa speaks at a lectern
Japanese foreign minister Yoko Kamikawa hosted the talks (AP)

“In order to have the prosperity in the region, we must ensure stability of the foundation in maritime, cyber and space domains,” she said.

“We Quad nations aim to protect the foundations of prosperity in the Indo-Pacific as we seek to achieve an international community of coexistence and coprosperity.”

Australia’s Ms Wong said the Quad nations were working to achieve a region that is governed by “accepted rules and norms where all of us can cooperate, can trade and thrive” and where “sovereignty is respected and competition is managed responsibly”.

The talks came after Japan and the United States held their “2+2” security meeting on Sunday, when they called China “the greatest strategic challenge”.

They agreed on further deepening military cooperation by making major upgrades to their command structures and bolstering Japanese production and repair of US-licensed weapons.