A report in London's Financial Times said senior American officials had criticised the UK's method of testing Huawei gear before it was used, claiming that it would be sufficient to avoid threats to the telecommunications system.
For nearly two years, the US has been pushing countries it considers allies to avoid using equipment from Chinese companies, Huawei foremost, in 5G networks. But the US has produced no proof to back up its claims that these products could be used to spy for China.
Only Australia and New Zealand have fallen in line with Washington's dictates, but Wellington has now indicated that the initial refusal for telco Spark to use Huawei gear is not the end of the matter. Huawei sued the US on 7 March, seeking to be reinstated as a telco supplier in the country.
This individual said: “One analogy that we can often use is, one minute you’re holding a 5G coffee cup that is transmitting back telemetric data on what the temperature is what the actual liquid is inside. And then the next moment that object can turn into something radically different.
“While a huge opportunity, it is also deeply concerning to us from the perspective of national security."
When the American official was asked about the UK National Cyber Security Centre which carries out tests on Huawei gear alongside employees of the company in a test centre built by the Chinese firm, he dismissed it as a "technical mandate".
And he added: “Ours is a much broader question about how trust is changing in the way in which 5G networks will work in the future. Right now, back doors exist by definition, that’s how the manufacturer runs the network.
“We understand that there are a number of different opinions about that. That’s the concern we have and we are making that very clear to our partners.”
Last month, as iTWire reported, Ciaran Martin, the head of the NCSC, said that any likely risk posed by Huawei was manageable.
"Because of our 15 years of dealings with the company and 10 years of a formally agreed mitigation strategy which involves detailed provision of information, we have a wealth of understanding of the company," Martin said.
"We also have strict controls for how Huawei is deployed. It is not in any sensitive networks – including those of the government. Its kit is part of a balanced supply chain with other suppliers. Our regime is arguably the toughest and most rigorous oversight regime in the world for Huawei."
iTWire has contacted Huawei for comment.