A possibility of Portugal being removed from the UK’s green list later of safe places to visit today unsettled airlines.
Several countries are expected to be added in the review, including the Canary Islands, Malta and Finland, with some Greek and Caribbean locations also possible additions.
Others, including countries in Asia such as Vietnam and Malaysia, might be downgraded to either an amber or red rating.
Portugal is also at risk due to a rise in the number of infections recently.
Prime Minister Boris Johnson said today that he would have “no hesitation” in reclassifying countries if the assessment of risk by the Joint Biosecurity Centre changes.
“We're going to try to allow people to travel, as I know that many people want to, but we've got to be cautious and we've got to continue to put countries on the red list, on the amber list, when that is necessary.
Visitors to an amber-rated country have to quarantine for ten days on their return and take tests after two and eight days while those returning from red-rated countries have to quarantine in a hotel for two weeks.
Airline operators have been pleading for the government to relax restrictions surrounding air travel and changes to the status of a destination such as Portugal where holidays have resumed would be a major setback.
Michael O’Leary, Ryanair PLC’s (LON:RYA) chief executive said yesterday that it was absolutely imperative that big tourist destinations are added to the green list.
"The restrictions should be lifted, we should be allowing British families to travel to the US and Europe, and also to return without having to complete useless PCR forms for people who've already been vaccinated," he told Sky News.
IAG, the owner of British Airways and Iberia, has also called for the US to be granted green list status given the importance of business travel.
Luis Gallego, IAG’s chief executive, said the US should be on the UK’s green list of countries due to its high rate of vaccinations.
Labour has already called for the traffic light system to be scrapped altogether due to the confusion.
A reported 300,000 people have travelled on holiday to amber-rated countries such as Greece and Spain even though official advice to visit only if it is essential.
Shares in IAG slipped to 3% to 203.4p, Ryanair 2% to €16.82 and Easyjet 2.3% to 987p.