Boris Johnson has told Tory rebels that coronavirus health certificates are a “proportionate” response to the threat of the Omicron variant, as he faces the prospect of the biggest revolt of his leadership.

The Prime Minister said his Plan B to tackle coronavirus this winter is necessary for public health, as about 75 Conservatives consider rebelling in Tuesday’s votes.

Tories are particularly opposed to making NHS Covid passes, displaying vaccine status or a negative lateral flow result, mandatory for entry to large venues such as nightclubs.

The measures are expected to be approved with Labour’s support, but that would be a significant blow to Mr Johnson’s leadership, as he faces anger for allegedly rule-breaking parties in the run-up to Christmas last year.

Westminster was on watch for the resignation of ministerial aides, with up to 10 parliamentary private secretaries reported to be preparing to quit to rebel against the plans.

Speaking to broadcasters during a visit to to a vaccination clinic near Paddington, west London, the Prime Minister said: “I think what everybody needs to recognise is a couple of things: that Omicron is a very serious risk to public health, and that it is spreading really fast and there’s no room for complacency.”

He said the vaccines mean the country is in an “incomparably better” position than last year, adding: “And I hope that people will also understand, colleagues in Westminster and around the country, will also see that the measures we’re putting in place are balanced and proportionate.”

Mr Johnson said the vaccine rollout means “we actually have an economy and a society that is more open than virtually any other in Europe”.

He added: “I will make my case to my friends, to the public, to everybody – what drives me in this is concern for public health, and what I think is absolutely obvious to everybody who studies the data is if we can get boosted now, protect ourselves now, then we will have a much, much better chance of having a protected NHS going into next year.”

The Plan B restrictions also include compulsory mask-wearing indoors in most public places, and guidance for people to work from home where possible.

NHS Covid passes showing full vaccination or a recent negative test will be required for entry to indoor venues containing more than 500 people, unseated outdoor venues with more than 4,000 people, and any venue with more than 10,000 people, from Wednesday.

Mr Johnson’s landslide victory in the 2019 general election left him with a Commons majority of about 80 MPs.

If around 75 Tories who have indicated their opposition vote against the measures rather than abstain, they would deliver an even bigger revolt than was seen against the strengthened tiered system of coronavirus restrictions in December last year, when 55 Tories voted against the measures.

There are expected to be “a number of votes” on the different regulations, Downing Street said.

Conservative MP Marcus Fysh, one of the rebels, was criticised for comparing the plans to the atrocities of the Nazi regime.

“We are not a ‘papers please’ society. This is not Nazi Germany,” he told BBC Radio 5 Live. “It’s the thin end of an authoritarian wedge and that’s why we will resist it.”

Marie van der Zyl, president of the Board of Deputies of British Jews, responded: “It is completely unacceptable to compare the proposed vaccine passports with Nazi Germany.

“We urge people, particularly those in positions of authority, to avoid these highly inappropriate comparisons.”

The Prime Minister’s official spokesman said: “We are facing a tidal wave of Omicron and these Plan B measures are a vital part of enabling us to buy time so that we can get more of these booster doses in arms and provide the protection that will protect both lives and livelihoods.

“On the issue of certification, as I said, it requires proof of a negative test unless you are double vaccinated, and it allows us to keep some of these settings open, which is vital for hospitality, where otherwise we would have had no choice but to close them, which no one wants to see.”