Analysis - The US Navy ship, the USS Tarawa, was first launched into service in the mid-1970s.

The old warship has been successfully decommissioned, and is about to be sunk by "experimental" means off Hawaii as part of the world's largest maritime war exercise, where New Zealand is taking part.

At sea, the militaries of almost 30 countries, led by the US, are learning to work together to sink a ship second only in size to an aircraft carrier.

At the same time, on land, their political representatives, led by the US, were meeting at the NATO summit in Washington, learning about plans for European security and Indo-Pacific security to come together like never before.

This is under a new plan for NATO cooperation with the Indo-Pacific 4, or IP4, partners - Australia, Japan, South Korea and New Zealand - on Ukraine, disinformation, artificial intelligence and cybersecurity. The IP4 meeting was chaired by Christopher Luxon.

"This marks new territory for New Zealand," wrote analyst Geoffrey Miller in The Diplomat this week.

It also marks new tensions in relations with China.

NATO allies called China a "decisive enabler" of Russia's war in Ukraine, a move Beijing declared a smear and "provocative", according to The New York Times.

Meantime, Chinese officials and state media have framed the RIMPAC war games as a "bloc confrontation" in the Asia-Pacific.

The US is not arguing with that: "World's largest naval exercise sends message to China," the government-run Voice of America headlined.

The sinking of the Tarawa also breaks new ground.

The US said it would be experimenting with 30 different ways to sink it, to test "new capabilities or use existing capabilities in different ways. There's going to be a number of experiments for the US but also with our allies and partners", a commander said.

The Pentagon used land-based missiles for the first time to sink an old navy ship in an exercise earlier this year. Land-based missiles would provide a way to penetrate the Chinese navy's hold on seas near Taiwan, analysts say.

Chinese media The Global Times has reported the experiments may be in case of war in the Taiwan Strait, as only China has amphibious assault ships of the size of the Tarawa. It could double as practice for sinking an aircraft carrier - but was a "completely futile" display of US power, officials said.

Defence Minister Judith Collins' office told RNZ on Friday, "We're not commenting on a Global Times story."

RIMPAC has been around for years, and China even once used to join in. Not anymore.

Chinese state media commentary from a military analyst claimed the US wanted to "coerce" other countries to join RIMPAC, and aside from "thugs" Japan, Australia and Canada, the others were only doing it to avoid offending Washington.

The Chinese Embassy in New Zealand warned in late June the US was trying to "hollow out" the principle that Taiwan is part of China, in violation of China's sovereignty.

The New Zealand Defence Force is stressing the Hawaii exercise boosts interoperability. The exercise's commanders have also talked about it building relationships and "proficiency".

"Every nation in the world that has interests in the Pacific and will adhere to the same values is more than welcome to participate," one commander said.

Local peace activists have focused on values, and called on New Zealand to withdraw, because the exercise includes the Israel Defence Force, when its assault in Gaza is continuing.

An OIA response to Peace Action Wellington, showed a hurried response at 7pm on 11 June from NZDF, in coordination with the Defence Minister's office, to media questions including, "Wondering if NZDF has a statement on this at all regarding whether it feels comfortable working alongside them [Israel] currently."

Ask the Americans, was the office of the Chief of Defence's response.

RNZ has subsequently asked the US Department of Defence a similar question, without a reply so far.

The New Zealand Defence Force also exercised alongside Israel and other countries in February in California, led by the US Space Force. Space is becoming highly contested between the US and China.

RNZ has asked Defence if it took into account the full range of international concerns and interactions around Israel's conduct in Gaza, when it decided to participate with it in the GS24 space exercise.

Military exercises have always been about the advantages of choosing who to partner with.

But increasingly they are also about who to partner against.

New Zealand has not formalised its ties to NATO to the same extent as the other three countries in IP4.

But the message from Washington is it wants to "institutionalise" the grouping, and at the meeting Luxon chaired, the NATO Secretary-General Jens Stoltenberg said:

"Our security is not regional. It is global."

A local expert Professor David Capie told RNZ the IP4-NATO agreement would be useful.

A US expert, Derek Grossman, tweeted: "So...NATO won't be coming to the Indo-Pacific, but four nations - Australia, Japan, New Zealand, and South Korea - may be coming to NATO as the 'IP4' grouping.

"Think of it as "NATO +4."'

China might.