The Government is facing potential defeat over its plans to force venues such as nightclubs to use so-called Covid passports as Labour said it would not back the proposals.
Labour said the scheme is “costly, open to fraud and is impractical”, and added that receiving two doses of a vaccine does not protect fully from the disease.
At least 42 Conservative MPs have already signed a petition launched by privacy rights group Big Brother Watch against Covid certification being used for “general services, businesses or jobs”.
With a Government majority of 80 it means there are no guarantees the plans, on which MPs have been promised a vote, would pass the Commons.
It comes after Prime Minister Boris Johnson announced on Monday that full vaccination would be a condition of entry to clubs and other venues with large crowds in England from the end of September.
Punters would need to use the Covid certificate option on the NHS app to be able to enter.
But a Labour spokesman said: “We need to see the detail of what the Government puts forward regarding vaccine passports.
“We oppose the use of Covid vaccination status for everyday access to venues and services. It’s costly, open to fraud and is impractical.
“Being double jabbed doesn’t prove you aren’t carrying the virus.
“Testing for access to venues would be more efficient, and would give people and businesses more certainty.”
Until September, nightclubs are being urged to make use of the function in the NHS app voluntarily.
But when asked whether there were any examples of venues having done so outside of pilot schemes, No 10 could not provide any.
The Prime Minister’s press secretary said on Wednesday: “We’ve set out the reasons why we are looking at this policy. There are obviously concerns about the spread of the virus in high-risk settings like nightclubs from international examples, and we need to do everything we can to stop the spread of the virus.
“We think it’s right that at the point at which everyone has had the opportunity to have both jabs we do mandate this to help add an extra mitigation in such high-risk settings.”