Matt Hancock has warned the government has to “keep this country safe” ahead of revealing which countries will be moved onto the green list – or taken off it.
Ministers are set to make the first update to the traffic light system introduced three weeks ago, with changes due to take place from 7 June.
The health secretary said on Thursday morning: “We have got to follow the data and of course, I understand why people want to travel but we’ve got to make sure we keep this country safe, especially because the vaccine programme is going so well.
“We have seen hospitalisations and deaths come right down and we have to got to protect the progress we have made here at home, whilst allowing for travel where it is safe.
“You have got to follow the data.”
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On Wednesday, Boris Johnson warned the government will have “no hesitation” in moving countries off the green list if necessary.
Giving nothing away, he said the government will “wait and see” what the Joint Biosecurity Centre recommends before announcing changes to the list.
Currently, Portugal and Iceland are the only viable tourist destinations on the green list, meaning people returning to the UK from those places only need to take one post-arrival COVID test and do not need to self-isolate.
Concerns have been raised about how the current private testing system will cope with more people if further countries are placed on the green list.
Rory Boland, travel editor of Which?, told Sky News “too many people are not getting their test back on time”.
But minister Victoria Atkins told Sky News the testing policy is “quite longstanding”.
She added: “The testing regime returning from overseas is very clear – that will stay.”
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PM urges caution over lockdown easing on 21 June
Travellers returning from amber list locations, including Greece, Spain, France and Italy, have to quarantine at home for 10 days and take two PCR tests.
The government has said people should only travel to amber list countries if absolutely necessary.
Only British and Irish nationals, or people with UK residency, are allowed to enter the UK from red list countries and must quarantine in managed hotels for 10 days and take two PCR tests.
There are hopes some of the Greek islands will be added to the green list, as well as Grenada, Antigua, Malta and Finland.
But there are also fears some southeast Asian countries including Malaysia, Thailand, Vietnam, Cambodia and Indonesia could be added to the red list, meaning 10 days in a quarantine hotel.
Each country is assessed based on a range of factors, including what proportion of a population is vaccinated, rates of infection, emerging new variants, and access to reliable scientific data and genomic sequencing.