A former CIA analyst has told a congressional committee thought should be given to removing New Zealand from the Five Eyes intelligence alliance because of what he says are Labour Party's links to the Communist Party of China.

New Zealand has been labelled the "soft underbelly" for China's efforts to infiltrate the Five Eyes international security and intelligence network.

A report published by the Canadian Security Intelligence Service is the latest warning of China's perceived political influence and interference in New Zealand.

However, Prime Minister Jacinda Ardern has said the issue had not been raised with her by any of New Zealand's Five Eyes partners - Australia, Canada, the US or the UK, adding that "I take my steer on these matters from official channels, not opinions expressed at a workshop".

The report, called China and the age of strategic rivalry, said "New Zealand provides a vivid case study of China's willingness to use economic ties to interfere with the political life of a partner country".

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"An aggressive strategy has sought to influence political decision-making, pursue unfair advantages in trade and business, suppress criticism of China, facilitate espionage opportunities, and influence overseas Chinese communities," it said.

Smaller states, like New Zealand, were "particularly vulnerable" to Chinese influence strategies, including the influence of politicians, business people, and media.

The report was published by CSIS but it did not reflect the spy agency's views, and was based on reports to CSIS during an academic workshop.

It referred to the economic, military, and intelligence advantages China could gain through influencing, or interfering in New Zealand business, media and politics.

The advantages included gaining access to the Five Eyes intelligence sharing network.

"New Zealand is valuable to China, as well as to other states such as Russia, as a soft underbelly through which to access Five Eyes intelligence."

ROSS GIBLIN/STUFF PM Jacinda Ardern says China's perceived influence isn't a security issue, and none of the Five Eyes partners have raised it with her.

It also said extricating New Zealand from its traditional security and defence partners would be a "major coup" for the Chinese Government's strategic goal of turning China into a global great power.

The report also looked at the potential advantages for China in New Zealand's arable land, its presence in Antarctica, and its influence in the Pacific Region.

"Some of these activities endanger New Zealand's national security directly, while others have a more long-term corrosive effect.

"The impact of China's political influence activities on New Zealand democracy has been profound: a curtailing of freedom of speech, religion and association for the ethnic Chinese community, a silencing of debates on the [People's Republic of China] in the wider public sphere, and a corrupting influence on the political system through the blurring of personal, political and economic interests."

It went on to say New Zealand was being targeted by a "concerted foreign interference campaign waged by the People's Republic of China", which aimed to gain support for the Chinese Government's political and economic agendas, and to seek access to strategic information and resources.

"China's efforts undermine the integrity of the New Zealand political system, threaten New Zealand sovereignty, and directly affect the rights of Chinese New Zealanders to freedom of speech, association and religion."

THOMAS PETER/AP Foreign Minister Winston Peters was the first coalition Government minister to visit China. He met with China's Foreign Minister Wang Yi last week. Peters has in the past referred to the growing influence of non-traditional partners in the region.

For a small state and former colony like New Zealand it could be a challenge as to how to defend the country against foreign political interference, the report said.

"It takes the political will of the government of the day and popular support to do so. If New Zealand can find a way to better manage its economic and political relationship with the PRC, it could become a model to other Western states."

The report, similar to others, raised the risk of the erosion of New Zealand's democracy and independence if the issue was not addressed.

Ardern said New Zealand's relationship with Canada was "very strong", especially with Prime Minister Justin Trudeau.

"I have had no indication that our Five Eyes membership is under question, from Canada or any other of our partners, nor have I heard that it has been raised with any of my colleagues."

New Zealand is vigilant against any interference intended to harm the country's values, institutions and economy, she said, adding that New Zealand regularly reviewed whether its policy settings were fit for purpose.

In the past, there had been changes to protect New Zealand's interests, and the national security system identified and managed risks of national significance.

"The existing protections we have in place include criminal law relating to some interference activities, electoral law and organisations' internal systems to protect against corruption and espionage.

"As I've said before, we're always looking to ensure that these tools protect New Zealand's economy and democracy," she said.

The NZSIS also had a core function to investigate foreign intelligence activity and interference in New Zealand and provide protective security advice to government agencies, Ardern said.

"I have confidence in the work they do to protect New Zealand's interests."

The report comes after a former CIA analyst Peter Mattis raised similar issues during a US congressional committee hearing.

Mattis said New Zealand and Australia faced "substantial problems with interference by the Chinese Communist Party".

"In both cases, the CCP has gotten very close to or inside the political core, if you will, of both countries. The primary difference between the two has simply been their reaction.

"With respect to the reactions, in New Zealand, both the last prime minister, Bill English, and Jacinda Ardern, have denied that there's a problem at all."

In his testimony, Mattis went on to say New Zealand's involvement in the Five Eyes group could be reconsidered by the other partners.

"I think that at some level the Five Eyes or the Four Eyes need to have a discussion about whether or not New Zealand can remain given this problem with the political core, and it needs to be put in those terms so that New Zealand's Government understands that the consequences are substantial for not thinking through and addressing some of the problems that they face."

Mattis told RNZ he based his testimony relating to New Zealand on New Zealand news reports, including those relating to National MP Jian Yang - a former trainer of spies - and a paper by Canterbury University academic Anne-Marie Brady, on China's growing influence and interference in New Zealand.