Ahead of a crunch decision on Monday, the head of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) said the science backed the move, which would make Britons safer.
“Certainly measures like stricter quarantines and putting people in hotels for long periods will have an impact,” Professor Peter Horby said.
“It’s up to the government to decide whether they think the imposition of those is worth the benefits that they’re likely to see.”
The comments came amid fresh accusations that ministers have lost control of Covid security at airports, with hundreds of passengers packed into a crowded room at Heathrow.
It was claimed that electronic gates were opened up and people allowed through without proper checks – prompting Labour to condemn “no controls and a quarantine system in disarray”.
It seems certain that, on Monday, a Cabinet committee will take the once-unthinkable step of requiring at least some arrivals to pay to stay in hotels for up to two weeks afterwards.
The fight appears to be over whether all must do so – or just passengers from high-risk countries, with many Tory MPs warning of another “devastating blow” to the aviation and travel industries.
The prime minister hinted that a crackdown is looming on Friday, saying he did not want to undermine the “success that the NHS has had in vaccinating 5.4 million people”.
“We may need to go further,” Mr Johnson said, when asked about tougher border controls, adding about the vaccine programme: “We don’t want to put that at risk by having a new variant come back in.”
Patrick Vallance, the chief scientific adviser, is known to be in favour, after admitting keeping the borders when the pandemic struck last March was his biggest regret of the past year.
Matt Hancock, the Health Secretary, and Home Secretary Priti Patel are believed to be pushing for all international arrivals – other than cross-Channel lorry-drivers – to be required to quarantine under strict conditions.
The cost to passengers could be significant – Australia has enforced confinement in hotels for up to 24 days, with travellers charged £1,500 or more.
Officials are also known to have examined contacting each person once a day, requiring them to send a photograph of themselves at their location.
These can then be checked using GPS data and facial-recognition software. Those who fail to comply within a set period receive a visit from police.
Such a crackdown would go much further than the closure of “air corridors’, last Monday, requiring everyone coming to the UK to produce a negative Covid test.