The top diplomats of Australia, India, Japan and the United States say their Indo-Pacific-focused bloc is not aimed at countering China but they have released a statement reflecting growing unease over China's influence in the region.

Meeting in New Delhi, the four foreign ministers barely mentioned China by name and insisted the so-called Quad is designed to boost their own national interests and improve those of others through enhanced co-operation in non-military areas.

Yet their comments at a joint public event on Friday and a written statement made clear the grouping exists to be an alternative to China.

They made repeated references to the importance of democracy, rule of law, maritime security and the peaceful settlement of disputes all of which Beijing regards with suspicion when coming from Quad members.

Australian Foreign Minister Penny Wong said the Quad "has a deep interest in the region remaining open, stable and prosperous, and respectful of sovereignty".

"We live in a region that's being reshaped and the question is, what is our response to that? We can either choose to play our part in that or we can choose to sit back and let that be decided by others," Wong told reporters after the meeting.

In a direct shot at China, which has become increasingly aggressive in the Pacific and alarmed its smaller neighbours by pushing claims to disputed maritime zones, the ministers said they viewed with concern "challenges to the maritime rules-based order, including in the South and East China Seas".

In an oblique reference to China, as well as Russia, they said they "are committed to co-operate to address attempts to unilaterally subvert the UN and international system".

And, just a day after China and Russia thwarted the G20 and developing nations from adopting a joint communique on Russia's war against Ukraine, the Quad endorsed language to which Beijing and Moscow objected, including that "the use or threat of use of nuclear weapons is inadmissible".

Asked about no joint G20 communique, Wong said: "I think everybody knows there are differences of views between great powers particularly on the issue of Russia and Ukraine.

"But whatever the difficulties on those issues, the G20 must continue to co-operate on key issues and must continue to seek to resolve differences."

Speaking at a group event at India's Raisina Dialogue, the four ministers maintained the Quad did not seek conflict with China but rather to promote democracy, good governance, transparency, digital security and global health and disaster relief.

"As long as China abides by the law and international norms and acts under international institutional standards this is not a conflicting issue between China and the Quad," Japanese Foreign Minister Hayashi Yoshimasa said.

US Secretary of State Antony Blinken said the group was not designed to blunt China's rise by demanding that countries align with Quad members or Beijing.

"Our proposition is not to say to countries in the region 'You have to choose'," he said. "Our proposition is to offer a choice, a positive alternative."

Wong and Indian Foreign Minister Subrahmanyam Jaishankar agreed.

"I prefer to think about what we are for, not about what we are against," Wong said.

AP and AAP