Ministers have been warned against introducing vaccine passports by a cross-party group of politicians.
More than 70 MPs, along with peers, have launched a campaign to oppose a move they say would be "divisive and discriminatory".
It comes after Labour leader Sir Keir Starmer suggested the "British instinct" could be against the use of such a scheme.
Prime Minister Boris Johnson yesterday defended the suggestion, stating "there's definitely going to be a world in which international travel will use vaccine passports".
During a trip to Middlesbrough, he told reporters: "You can see already that other countries, the aviation industry, are interested in those and there's a logic to that."
In a pledge, signed by Jeremy Corbyn and Sir Ed davey, as well as other prominent figures such as Conservative former leader Sir Iain Duncan-Smith, Labour former shadow chancellor John McDonnell and ex-Lib Dem leader Tim Farron, the group warns the Government against bringing in such a proposal.
The pledge states: "We oppose the divisive and discriminatory use of Covid status certification to deny individuals access to general services, businesses or jobs."
Tory MP Sir Graham Brady, a signatory to the pledge, insisted that the aim should be to return to normal life.
He explained: "Covid-status certification would be divisive and discriminatory.
"With high levels of vaccination protecting the vulnerable and making transmission less likely, we should aim to return to normal life, not to put permanent restrictions in place."
Sir Ed Davey said he hoped to turn the tide on "creeping authoritarianism" from Downing Street.
He said: "As we start to get this virus properly under control we should start getting our freedoms back, vaccine passports - essentially Covid ID cards - take us in the other direction.
"Liberal Democrats have always been the party for civil liberties, we were against ID cards when Blair tried to introduce them and we are against them now."
He added: "I hope we can start to turn the tide on the creeping authoritarianism we are seeing from Number 10 across a broad range of issues."
Labour peer Baroness Shami Chakrabarti suggested that the use of Covid passports would be a "step too far".
"International travel is a luxury but participating in your own community is a fundamental right," said Baroness Chakrabarti.