Dominic Raab’s reassurances came as the embattled travel group met shareholders and creditors on Sunday in a final attempt to piece together a rescue deal.
The 178-year-old company has issued a last-gasp plea to its lenders to reduce a £200m funding demand as the travel agent was just hours from possible insolvency.
If the company collapses into administration it would trigger Britain’s biggest-ever peacetime repatriation operation, as 165,000 holidaymakers will need to be flown back to the UK.
Speaking to the BBC, Mr Raab said: “We have got all the contingency planning to make sure no one will be stranded.
“I don’t want to give all the details of it because it depends on the nature of how people are out there, whether they have got a package holiday or whether they just paid for the flights and sorted out something separately.”
He added: “But I can reassure people that in the worst case scenario, the contingency planning is there to avoid people being stranded.”
Britons who are currently on holiday with Thomas Cook – as well as those who are about to travel – have faced a nervous wait as the business tries to avert collapsing into insolvency.
Thomas Cook customers who were staying in the Les Orangers beach resort in Hammamet, Tunisia, said they were not allowed to leave the hotel compound on Saturday night because of the crisis facing the travel operator.
Guests said hotel staff told them they would have to pay for their stay before leaving, even though holidaymakers said they had paid Thomas Cook for their trip.
Gary Seale, from Shrewsbury in Shropshire, said on Facebook that security “refused to let us out of the hotel and barricaded us in”.
Laura D An posted a video on social media on Saturday of people locked within the grounds of the hotel and said guests were “literally being held hostage”.
She said: “There’s people from Thomas Cook trying to get out of the hotel, however security and hotel management aren’t allowing anyone to leave the hotel.
“They’ve literally barricaded the front gates, the coach is there trying to collect people to go to the airport to leave to go home, and management aren’t allowing it.”
The holidaymaker added: “We’ve got people there with their cases waiting to go home on their flight that they’ve paid for, but they’re not allowed to leave.
“Thomas Cook aren’t informing of us of anything. We are literally being held hostage in a hotel in Tunisia.”
Thomas Cook’s customer care page tweeted on Sunday: “We’re aware a small number of customers were asked to pay for their hotel before leaving Tunisia, we have refunded all who paid on their credit cards.
“Thomas Cook will not be sending any new arrivals to Les Orangers, Tunisia.
“We continue to support customers in all our resorts.”
Thomas Cook had reassured worried customers on Saturday night that their flights would continue to operate as normal and all their package holidays are ATOL-protected.
With 20,000 jobs across the group at risk, including 9,000 in the UK, the Transport Salaried Staffs’ Association, which represents workers at the company, said ministers should be ready to offer “real financial support”.
The association’s general secretary Manuel Cortes called for an urgent meeting with Business Secretary Andrea Leadsom.
He said in a letter: “It is incumbent upon the government to act if required and save this iconic cornerstone of the British high street and the thousands of jobs that go with it.”
Shadow business secretary Rebecca Long-Bailey said: “The government faces a simple choice between a £200m government cash injection to save the company now versus a £600m bill to repatriate UK holidaymakers.”
More than 3,000 of the UK job losses would be in Greater Manchester.
The city’s mayor Andy Burnham tweeted on Sunday: “I’m hearing today is make-or-break for @ThomasCookUK, its customers and the 3000+ people working for them in Greater Manchester.
“Situation is rescuable but much more likely with government support.
“About to write to @10DowningStreet asking for an urgent intervention.”
The Civil Aviation Authority is spearheading plans for the repatriation operation should it be needed, and the exercise has been code-named Project Matterhorn.
In recent days, the London-listed company has explored a multitude of options to raise the remaining £200m required by its banking syndicate.
Many of those have been discounted because there is insufficient time to implement them before Thomas Cook runs out of money.
A plan for Triton Partners to buy Thomas Cook’s Nordic operations was still under discussion on Saturday, as was a proposal to keep its airlines in the UK, Germany and northern Europe out of administration while letting its British tour operating arm fail.
However, one insider suggested that neither was likely to be viable.
A request for emergency government funding was made by Thomas Cook earlier this week, with executives arguing that the cost to taxpayers would be dwarfed by the bill incurred by the repatriation.
One insider described the widely reported £600m tab, however, as being “a gross overestimate of the cost to taxpayers”.
A government spokesman said: “We recognise it’s a worrying time for holidaymakers and employees.
“The financial circumstances of individual businesses are a commercial matter, but the government and the Civil Aviation Authority are monitoring the situation closely.”
Current trading at Thomas Cook is understood to have remained difficult for months, with the ongoing political crisis in Westminster contributing to soft consumer demand for autumn and winter bookings.
On Friday, shares in Thomas Cook closed at 3.45p, more than 95% lower than at the same point last year.
The British company was founded in 1841 by a 32-year-old cabinet-maker and former Baptist preacher who began offering one-day rail excursions from Leicester to Loughborough for a shilling.
From there, it went on to become one of the world’s largest holiday companies, marking its 175th anniversary three years ago.