The US government has initiated an extraordinary outreach campaign to foreign allies, trying to persuade wireless and internet providers in these countries to avoid telecommunications equipment from Chinese company Huawei, according to a Wall Street Journal report.

The move will ramp up pressure on GCSB Minister Andrew Little and Communications Minister Kris Faafoi, who both say the government has yet to make a decision on whether Huawei should be blocked form 5G upgrades in NZ - as security agencies in the US and Australia have already recommended.

Officials familiar with the current effort say concerns about telecom-network vulnerabilities predate the Trump era and reflect longstanding national-security worries, the Journal says.

It notes that the push comes as telcos around the world prepare to buy new hardware for 5G, the coming generation of mobile technology.

US officials say they worry about the prospect of Chinese telecom-equipment makers spying on or disabling connections to an exponentially growing universe of things, including components of manufacturing plants, the Journal says.

The paper quotes an un-named US official who says, "There are additional complexities to 5G networks that make them more vulnerable to cyberattacks."

While US suspicion of Huawei is longstanding, its previous efforts have focussed on keeping the Chinese company out of the US. Now, it's broadening its battle lines.

Here, Little and Faafoi have been notably muted in their comments compared to politicians in the US and Australia, however. Little has said that New Zealand will make its own decision.

Pressure could be eased by the fact NZ does not host US forces - unlike Italy, Japan and Germany, whose telcos all use Huawei kit.

"One US concern centers on the use of Chinese telecom equipment in countries that host American military bases, according to people familiar with the matter," the Journal says. "The Defense Department has its own satellites and telecom network for sensitive communications, but most traffic at many military installations travels through commercial networks."

Huawei NZ deputy chief executive Andrew Bowater says there has never been any evidence tabled that his company is involved in espionage - and that reports inevitably quote un-named sources talking about un-specified incidents.

Under the Telecommunications (Interception Capability and Security) Act (2013), the GCSB has to approve technology used by network operators for telecommunications network upgrades, Bowater says.

Huawei faced similar scrutiny by the GCHQ in the UK, which shared results with New Zealand. It has passed.

However, Bowater also says Huawei will not bid for Spark, Vodafone or 2degrees' core 5G business, citing "sensitivities."

Huawei will bid to put 5G gear on the three telco's cellsites.

The company says Spark's 5G Lab, which includes test 5G cellsite with a core (or brains of the network) provided by US Cisco and RAN (radio access network) gear from Huawei, proves the core can be isolated.

And while Huawei stridently refutes all espionage allegations as motivated by politics or protectionism, Bowater's counterpart across the Tasman has also pointed out, for those who do buy into the accusations, that Nokia Networks and Ericsson have joint enterprises with local manufacturers in China.

Any government bid to block Huawei in NZ would be a lot more complicated than Australia.

Huawei was blocked from Australia's public-private National Broadband Network (NBN) but, following advocacy by former Prime Minister and active Huawei booster John Key, its gear is riddled through the Ultrafast Broadband (UFB) and Rural Broadband Initiative (RBI) networks, as well as various parts of Spark, Vodafone and 2degrees' existing infrastructure.

Banning Huawei from 5G would imply all of its gear would have to be ripped out and replaced.

Telecommunications Users Association head Craig Young says that would be a disruptive and expensive process.

Spark and 2degrees have both said they want the government to produce proof of wrongdoing before any Huawei ban.

Faafoi and Little did not immediately respond to requests for comment.