British Prime Minister Boris Johnson has said he did not want to dismiss foreign investment, but security was tantamount, as he was asked whether he had told US President Donald Trump the UK would not involve Huawei in developing a 5G network.

"On Huawei and 5G, I don't want this country to be unnecessarily hostile to investment from overseas," Johnson told reporters during a post-Nato press conference.

"On the other hand, we cannot prejudice our vital national security," he added. 

"Nor can we prejudice our ability to cooperate with other vital Five Eyes security partners - and that will be the key criteria that informs our decision about Huawei."

Five Eyes is an alliance comprising Australia, Canada, New Zealand, the UK and the US for joint cooperation in signals intelligence.

Britain has delayed a decision on Huawei and none is expected before the general election on 12 December, when Johnson's Conservatives are hoping to be returned to power.

The US has been pressuring allies, including the UK, to exclude the firm because it argues Huawei has close ties to the Chinese government and its equipment could pose a security threat.

Read more: What is 5G?

President Trump, speaking at the Nato summit in the UK, had earlier said of the use of Huawei technology: "I do think it's a security risk, it's a security danger."

"I spoke to Italy and they look like they are not going to go forward with that. I spoke to other countries, they are not going to go forward. Everybody I've spoken to is not going to go forward," the US president added.

Nato leaders released a summit declaration on Wednesday saying that it was necessary to make sure the technology was secure before adapting it for use among members of the military alliance.

"Nato and Allies, within their respective authority, are committed to ensuring the security of our communications, including 5G, recognizing the need to rely on secure and resilient systems," the declaration states.

In response, a Huawei spokesperson said: "We're confident the UK government will continue to take an objective and evidence-based approach. 

"We agree with the 'need to rely on secure and resilient systems' as outlined in the Nato Declaration - our 5G equipment is trusted by leading telecoms operators globally and we will continue to provide our customers with innovative, secure and resilient products."