British ministers and officials have been less than impressed by an anti-Huawei presentation delivered this week by members of a United States delegation.

The high-level visitors from US President Donald Trump's administration delivered their message "dramatically" on Monday, The Guardian newspaper reported, but their contention that the Chinese technology giant poses a security risk to the United Kingdom's 5G networks reportedly came with no new evidence.

The newspaper said the feedback it got after the presentation suggests British intelligence agencies are not inclined to alter their assessment that Huawei poses a manageable security risk, a conclusion shared by the BBC.

A British government source told the paper: "We'd already anticipated the kind of threat that the US material demonstrates, and factored that into our planning."

The UK government is expected to make a decision imminently on whether it will allow the company to participate in the nation's 5G rollout. The government of then-prime minister Theresa May made an interim decision last spring, saying the use of Huawei components in some "non-core" areas of the network was acceptable.

The delegation said before it made its pitch that it had fresh technical evidence.

After the delegation finished, its members met journalists and one delegate insisted it would be "nothing short of madness" if Britain allowed Huawei to supply equipment for high-speed 5G mobile phone networks because components could feature secret "back doors" that allow espionage.

Despite the claims, no such back doors have been found and no proof of their existence offered and Huawei has said its equipment is safe.

UK Prime Minister Boris Johnson said this week he does not want to jeopardize Britain's intelligence-sharing relationship with the US but that he also does not want to stymie economic growth by failing to roll out 5G in a timely manner.

He told the BBC Breakfast program that "the British public deserves to have access to the best possible technology".

"We want to put in gigabit broadband for everybody," he said. "Now, if people oppose one brand or another, then they have to tell us what's the alternative."

Separately, Reuters reported that German Chancellor Angela Merkel was set to meet conservative lawmakers on Thursday to discuss whether Huawei should be banned from that nation's 5G networks.

Her party has partnered with the Social Democrats to form a coalition government but the junior partner has been reported to want to ban Huawei from German networks. Merkel had previously said she did not support an exclusion.