Pub goers could be asked to provide a vaccine certificate, Boris Johnson has told MPs, saying it “may be up to individual publicans”.
A review is looking into whether people should have to prove they have been vaccinated, as lockdown measures ease.
A government source told the BBC that the option of allowing people to show a negative test was also being looked at.
But Tory MP Steve Baker said it was a “ghastly trap” and unfairly penalised those advised not to have a vaccine.
Mr Johnson also said it seemed “wholly responsible” for care companies to require their workers to be vaccinated.
Speaking to the House of Commons Liaison Committee, Mr Johnson added that “the principle is there” in terms of professions requiring certain vaccines when “entrusted with care of a patient”.
But the idea of asking pub goers to show a vaccine certificate was strongly rejected by Mr Baker.
“First they said we’ll need them to watch the football, and today that it may be papers for the pub,” he said.
He warned that such a situation would prevent pregnant women – who have been advised not to take the vaccine – from “taking part in society”.
He also expressed concern that business would be able to turn away customers “from communities which have shown an unfortunate hesitancy to take up the offer of a vaccine”.
“We must not fall into this ghastly trap,” he said.
Kate Nicholls, the chief executive of UK Hospitality, said the sector should not be “subject to mandatory vaccination certification”.
“It is simply unworkable, would cause conflict between staff and customers and almost certainty result in breaches of equality rules,” she added.
Ministers, and the devolved administrations, have set out plans for how the rules they imposed will be rolled back.
But there are still question marks over what will take the place of the laws we have lived with for so long.
Mr Johnson today was happy to sketch out how that question could in part be answered, in a way that not all of his party will like.
He made clear that he was willing to countenance the idea of ‘jabs for jobs’ and held open the possibility that bars might ask for ‘papers for pints’.
When tests are widely available, proof of a negative test, is also being considered as a tool to help venues open up
The government is reluctant to make any of this compulsory for everyone.
But it seems that proving our Covid status, through the vaccination, or a test, is likely to be part of our lives in the medium term.
During the committee – which is made up of senior MPs – Conservative William Wragg asked Mr Johnson if vaccine certificates were “compatible with a free society such as ours”.
Mr Johnson said the concept “should not be totally alien to us” as doctors already have to have hepatitis B jabs
Mr Wragg then asked, what about “ordinary citizens going to the pub?” and the prime minister replied: “That’s the kind of thing that may be up to individual publicans.”
Pushed further, Mr Johnson said: “I find myself in this long national conversation thinking very deeply about it” adding that the public “want me as prime minister to take all the action I can to protect them”.
On Thursday, MPs will debate and vote on renewing the emergency powers granted by the Coronavirus Act.