China is allegedly buying political influence in the Pacific through a soft power campaign of debt-trap diplomacy and "economic blackmail", according to senior US military leaders who say New Zealand is a key player in maintaining a "free and open" region.

The major identified threats to Pacific peace and security were highlighted by high-level military officers across the Army, Navy and Air Force in a series of remarkably candid and frank briefings with visiting New Zealand journalists at the US Indo-Pacific Command (INDOPACOM) headquarters in Honolulu last week.

The US fears the People's Republic of China has closed the gap in military capacity in recent years, forcing them to recruit allies – countries with a "shared set of values" – to keep up with Beijing.

Its military accuses the communist government of attempting "debt-trap diplomacy" by "air-dropping" billions of dollars into Pacific economies to gain political advantages in the geographically-vast and critical area, repeatedly citing the example of the infamous Hambantota port deal in Sri Lanka.

It all forms part of what the US believes is China's long-term goal of trying to de-legitimise America's sphere of influence in the Pacific.

"This is the new game on the block. This is a new phenomenon in the Pacific," says INDOPACOM's acting chief of staff, Major-General Suzanne Vares-Lum, a former US spy chief during the Iraq War.

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It was clear from the briefings that the US will start to depend on New Zealand to do more work in a region stretching "from Hollywood to Bollywood and from polar bears to penguins".

"We really appreciate the partnership with New Zealand,"

In a briefing at the US Pacific Air Forces (PACAF) headquarters, the Pacific, which is home to five of the world's eight nuclear powers and 75 per cent of the largest missile arsenals, has seen a "return of great-power competition".

China poses the greatest long-term and immediate threats, it said, with its idea of a new international order clashing with the US vision for a free and open Indo-Pacific.

PACAF admits the US military advantage has "eroded" in recent years and now faces "a contest for air superiority". It needs to "rethink how we think about the Indo-Pacific theatre" and strengthen alliances and recruit new partners to "enhance lethality and interoperability".

The US also suspects China has been able to increase its military capabilities though "cyber-incursions", although it's understood they don't have any evidence of specific examples, and don't know whether software, hardware, satellites or undersea cables have been targeted.

It's understood that the US Navy also eagerly await the return of the Royal New Zealand Navy's two Anzac class frigates, HMNZS Te Kaha and HMNZS Te Mana which are undergoing combat management system upgrades in Victoria, Canada.

Air Force Colonel Dan Munter believes New Zealand is important in helping to contribute to the "rules-based international order" and welcomed the New Zealand government's recent upgrade of the ageing Orion aircraft with four new high-tech Boeing P-8A Poseidon maritime patrol planes which are more compatible with the US air fleet.

It's understood that the US Navy also eagerly await the return of the Royal New Zealand Navy's two Anzac class frigates, HMNZS Te Kaha and HMNZS Te Mana which are undergoing combat management system upgrades in Victoria, Canada.

Vares-Lum said a well-respected New Zealand has "a lot of ability to influence" in Oceania and the South Pacific, while heaping praise on the New Zealand Defence Force (NZDF) for "punching above its weight class" in policing of illegal fishing and illicit trafficking of goods and people.

"We really appreciate the partnership with New Zealand," she said.

Vares-Lum also welcomed opportunities for joint military training exercises and disaster relief operations, as well as information and intelligence sharing.

All of the military sources spoken to by the Herald stressed the US simply wanted a "free and open" Pacific, not just for themselves but for all "like-minded" countries.

Its own "soft power" strategies include education, partnering to bolster smaller nations' security forces, economic development and investment, and the deployment of US Peace Corps.

One senior leader said the US Strategic Engagement Plan, which looks to strengthen its ties with allies, is the "opposite of blackmail" and provides a holistic "here to help" approach.

Other threats to the Pacific, according to the US military, include Russia, which continues to act as a "spoiler" in the region for America, with increasing long-range bomber flights, along with North Korea, Iran, terrorism, and climate change.

"We want to maintain a strong defence so that we never have to use it," Vares-Lum said.

"It is essential in maintaining peace and security."