Appearing on the BBC's Panorama program on Monday night, Dr Ian Levy said he had yet to be convinced that a remedial program, promised by Huawei to sort out issues that were identified last year, was going to be effective.
He said this meant Huawei gear could be banned from Westminster and other sensitive parts of the country and kept out of the core of 5G networks in the rest of the UK.
"The security in Huawei is like nothing else — it's engineering like it's back in the year 2000 — it's very, very shoddy," Dr Levy said, according to the BBC.
Last month, a report from the Huawei Cyber Security Evaluation Centre Oversight Board in the UK identified a number of issues in the company's approach to software development, and said these were significantly increasing risk to operators and needed ongoing management and mitigation.
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 Washington 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 indicated that the initial refusal for telco Spark to use Huawei gear is not the end of the matter. That stance was reiterated by Prime Minister Jacinda Ardern during a one-day China visit in April. Huawei sued the US on 7 March, seeking to be reinstated as a telco supplier in the country.
Ryan Ding, chief executive of Huawei's carrier business group, told Panorama that he planned to spend more than the US$2 billion already committed to tackle the issues that had been identified.
"We hope to turn this challenge into an opportunity moving forward," he said.
"I believe that if we can carry out this program as planned, Huawei will become the strongest player in the telecom industry in terms of security and reliability."
Mobile UK, a lobby group for telcos in the UK that represents Vodafone, BT, O2 and Three, has said that if Huawei is banned from 5G networks in the UK, it could cost the economy up to £6.8 billion (A$11.73 billion) and delay the 5G launch by up to two years.
The group said:
"A partial to full restriction on Huawei in the telecoms supply chain could result in an 18-24 month delay to the widespread availability of 5G in the UK;
"A delay to launch will result in the UK failing to be a world leader in 5G – something that has been central to the UK government’s 5G strategy;
"Using the government’s own estimates on the benefits of 5G, the cost to the UK economy of a delay in rollout is calculated at between £4.5bn and £6.8bn; and
"As well as the measurable financial impact, the UK will also suffer in terms of lower inward investment and lost productivity gains through stagnation of digital infrastructure."
iTWire has contacted Huawei for comment.