British officials are split over whether to drop quarantine requirements for visitors who are inoculated with non-UK approved vaccines.
At Westminster, ministers are under pressure to try to revive the fortunes of the travel industry after months of border restrictions.
Health Secretary Matt Hancock last week said the government was making progress on easing entry requirements, with the Cabinet considering the end of 10-day quarantine for fully vaccinated passengers from amber list countries.
However, officials are still to decide whether any new regime would be limited to returning British citizens or apply to all arrivals.
It is understood that non-UK approved vaccines and verification of inoculation status are complicating matters.
People in Britain can demonstrate their vaccination status by using a QR code on the National Health Service app, but there is no means of verifying foreign vaccine certificates.
Chancellor Rishi Sunak and Transport Secretary Grant Shapps are pushing for quarantine-free entry for vaccinated travellers from July 19, The Times reported.
However, Mr Hancock and Foreign Secretary Dominic Raab want the plan delayed until August, and Prime Minister Boris Johnson is reported to be in agreement.
Plans to drop quarantine requirements for fully vaccinated passengers are expected to be announced on Thursday as part of the review of the traffic light system.
On Thursday, Environment Secretary George Eustice spoke of the government’s caution regarding foreign travel for vaccinated passengers.
"Nobody likes the draconian restrictions we have had to put in place over this last year as we have wrestled with the pandemic,” he told Sky News.
"We are being cautious because the biggest threat still to our progress against this pandemic and the great progress we have made on vaccination is that there will be another variant somewhere that maybe hadn't been properly detected in another country and that variant is more resistant to vaccination.”
Four vaccines are approved for use in the UK – Pfizer-BioNTech, Moderna, AstraZeneca-Oxford and Johnson & Johnson – and the EU uses the same vaccines.
In April, Ireland changed its hotel quarantine rules to allow travellers vaccinated with EU-approved vaccines to quarantine at home.
