The UK transport secretary has refused to say he would book a foreign holiday for himself and his family yet, even as travel restrictions are eased for several destinations.

Grant Shapps warned anyone looking to travel abroad that the rules could change at short notice after Malta, Madeira and the Balearic islands, among others, were added to the list of countries from which travellers could return without having to quarantine.

But there was concern across the beleaguered travel sector, with one prominent figure accusing the government of being “overly cautious”.

Shapps said: “People will have to come to their own decisions ... If people are in a situation where, from next week, they wanted to get away then these are the places where you can go for the purposes of holiday, of course, being aware of all the caveats about the risk of things changing because … that happens with quite a lot of regularity.”

And he acknowledged that the ongoing pandemic meant the status of any country could change with no notice, with those on the “green watchlist” most likely to see harsher restrictions reimposed.

“Whoever is booking to go anywhere this summer, travel insurance, making sure your flights are changeable and making sure the accommodation is changeable – all those things are going to be very, very important this year. And I think people need to weigh up whether that is going to work for them or not,” he told Sky News.

Asked if he would rather people simply did not travel abroad at all, therefore, he told BBC Breakfast: “No, that’s not my message at all. I’m transport secretary if people travel domestically in the UK or abroad.

“We must be aware that, when you travel abroad this year, there are complications because of this pandemic that, a couple of years ago, wouldn’t have existed and wouldn’t have been a factor. But it is for individuals to make that decision.”

The holiday company On the Beach said it would not be taking new bookings for July and August while so much uncertainty remained about countries on the watchlist.

Criticising ministers’ caution, the Airport Operators Association chief executive, Karen Dee, said: “Any extension of the green list is welcome, however small, but we also have to be realistic: this is not yet the meaningful restart the aviation industry needs to be able to recover from the pandemic.”

It was announced on Thursday evening that Malta was among 14 new countries and territories to be added to the green list or green watchlist from next Wednesday at 4am.

Explaining the difference, Shapps said people returning from any of those countries would not have to quarantine, provided they test negative for Covid before and upon their return. But he said ministers harboured greater concern over the green watchlist countries. These included all the newly added destinations, except Malta.

The lists are reviewed every three weeks, meaning that the next announcement will be on Thursday 15 July.