The president of the UK's upcoming climate change conference is under fire for travelling to more than 30 countries in seven months.
Several places visited by Alok Sharma were on the Covid red list - but he used an exemption for ministers to avoid quarantine on his return.
The government said face-to-face meetings were "crucial" ahead of the COP26 climate summit.
But opposition parties have accused Mr Sharma of hypocrisy.
Wales' First Minister Mark Drakeford called his itinerary - which was all published on government websites - "inexplicable".
He said government ministers should "demonstrate that we too mean business" in tackling climate change if they want the public to follow suit.
Liberal Democrat MP Christine Jardine said it was "completely and utterly irresponsible" for the minister to come back from red list countries without quarantining.
The Daily Mail - which first reported the story - also claimed Mr Sharma held a meeting with Prince Charles days after returning from Bangladesh - a red list country - before going on a visit to a primary school.
Mr Sharma tweeted pictures of his meeting with the prince, including one showing participants sitting inside without wearing masks.
He is currently in Brazil - also a red list country - and has tweeted that he is having "constructive meetings".
Mr Sharma left his post as business secretary in January to take over the presidency of COP26 - the United Nations climate change conference due to take place in Glasgow in November.
Since then, he has met with dignitaries across the globe to discuss climate commitments ahead of the conference - despite the ongoing pandemic.
Asked by the BBC's Nick Robinson in June how he defended his air travel when he is leading on environmental policy, he said it was "really important" to meet other governments to discuss plans and the visits had been "targeted".
But Mr Drakeford said ministers "couldn't exempt themselves" from changes required to tackle climate change.
He told BBC News: "I accept that there are some crucial meetings where being in the same room with other people does bring a new dimension to your ability to make progress.
"[But] was that necessary 30 times in the lead up to COP26? That, I think, is a completely different matter.
"We need to maximise the way in which we avoid travel, and we avoid adding to the emissions that creates and we need to lead by example, and I am afraid that is not what we are seeing."
The Green Party's Baroness Jones also said she "despaired at the inability of Tory ministers to grasp their hypocrisy of talking about our climate emergency then behaving as normal."
But Conservative Culture Minister, Caroline Dinenage, said Mr Sharma had a "huge job" with the upcoming conference and success could "only be achieved by these really strong collaborative conversations that [he] has been pursuing around the world".
And Allegra Stratton, the PM's spokeswoman for COP26, said Mr Sharma had travelled to "meet key players and negotiate success for us all," and was doing "vital work".
A government spokesman added: "Helping the world tackle the climate emergency is an international priority for the government.
"Virtual meetings play a large part, however face-to-face meetings are key to success in the climate negotiations the UK is leading as hosts of COP26 and are crucial to understanding first-hand the opportunities and challenges other countries are facing in the fight against climate change."
It is also understood the government plans to offset the emissions associated with travel by Mr Sharma and other UK officials in the run up to COP26.
Alok Sharma is not alone in clocking up the air miles.
US Special Envoy for Climate John Kerry has made official visits to Bangladesh, Belgium, China, Egypt, France, Germany, India, Russia, Saudi Arabia, South Korea, the UK and the UAE this year.
Frans Timmermans is the EU executive vice president for the European Green Deal.
He seems to have been travelling less, having been in South Korea and Singapore in July, with visits to the Czech Republic, Germany, Italy and the UK earlier in the year.
Mr Sharma is also facing further criticism for not quarantining on his return from the trips, including from red list countries, such as Bangladesh and Turkey.
UK citizens are advised not to travel to red list countries "except in the most extreme of circumstances" - but if they do, they are required by law to quarantine in a government-approved hotel for 10 days at a cost of £2,285 for one adult.
Breaking this law can result in a fine of up to £10,000.
However, government ministers can claim an exemption from this rule to carry out "essential government work".
Other groups can claim the exemption, including elite sportspeople, certain business executives, diplomats, lorry drivers, and border officials.
Speaking to the BBC, the Lib Dem's Ms Jardine said the government was showing "yet again [that] there is one rule for them and a different rule for the rest of us".
She added: "Again this government is making up a rule to suit this government and not other people. What about all the families who would love to be in the room for the christening of a grandchild or the wedding of a relative across the world? They would love to be in the room and they are not there.
"The rest of us the rest of the time have learned to make use of the electronic facilities that are there, the advances in technology.
"This government is losing touch completely with what the actual needs, demands and priorities of the ordinary people in this country are."