Military planners are scrambling to find barracks to house asylum seekers and "accelerate" the closure of migrant hotels, John Healey has confirmed.
The Defence Secretary said the Armed Forces have been drafted in to help "restore control of our borders".
And they are working alongside the Home Office to end the asylum accommodation crisis, which has led to taxpayers shelling out £5.7m a day on hotels and migrants being moved into flats and houses across the country.
Yvette Cooper was replaced by Shabana Mahmood as Home Secretary on Friday after the number of migrants crossing the Channel soared during Labour's first year in office.
Mr Healey said: "What you're seeing from Keir Starmer now is a recognition that this isn't just a job for the Home Office.
"It's an all of Government effort, and we, in the Ministry of Defence, will play our part.
"We've got planners alongside the Home Office. We're looking at military and non-military sites for potential temporary accommodation.
"And this is about trying to restore control of our borders, which was lost over the last five or six years and the confidence of the British people that we can keep them secure and we can reflect our values."
Two former military sites - MDP Wethersfield, a former RAF base in Essex, and Napier Barracks, a former military base in Kent - are already being used to house asylum seekers after being opened under the previous government.
BBC presenter Laura Kuenssberg asked: "I just want to be very clear about what you're saying here.
"You say military planners will be involved in helping to manage what many people see as a crisis in migration.
"Are you talking about members of the Armed Forces being involved in enforcing our borders?"
Mr Healey confirmed: "Military planners are alongside the Home Office, planners in Border Command and planners alongside the Home Office, looking at the way we can accelerate the closure of asylum hotels, the development of alternative accommodation that can deal with people who are coming to this country illegally, who may need to be processed, may not have a right to stay here and will be deported in bigger numbers as well."
More than 32,000 people are currently staying in hotels, costing taxpayers £5.77m every day.
Military sites, former student accommodation, abandoned care homes, empty tower blocks and converted houses and flats could all be used to house asylum seekers.
And former Home Secretary Yvette Cooper revealed "industrial sites" are now under active consideration as well.
Dozens of asylum hotels are expected to close after they became the focal point of several demonstrations in recent months.
Ministers are also close to agreeing a returns deal with Germany, having already secured one with France.
An estimated 1,000 people arrived in the UK by small boat over the course of yesterday (Saturday) and French authorities said 24 people were rescued while trying to cross the Channel.
Mr Healey said Ms Mahmood had been brought into the Home Office as part of Sir Keir Starmer's plan of "going up a gear" in Government.
Asked why Yvette Cooper had been moved out of the Home Office, the Defence Secretary told Sky News's Sunday Morning With Trevor Phillips: "Because I think Keir Starmer has decided that as part of going up a gear, demonstrating the next phase of delivery, he wants Shabana Mahmood, who's done so well getting to grips with the prisons crisis, to do that in the Home Office.
"And he's going to use the skill that Yvette Cooper has shown in striking a returns deal with France, which the Conservatives couldn't do (in the Foreign Office)."
Former borders minister Dame Angela Eagle and former policing minister Dame Diana Johnson were moved to other departments in the clear-out.
Reform UK's head of policy, Zia Yusuf, denied claims that migrants will be housed in shipping containers if Nigel Farage wins the next election, insisting the party would use "purpose-built modular steel structures".
Speaking on Sky News, Mr Yusuf defended proposals for rapid-build detention facilities, citing international examples.
"We can look around the world at where things have worked and worked well," he said.
"President Trump stood up 3,000 detention beds in eight days. That was this year in the state of Florida - using steel modular structures."

When presenter Trevor Phillips asked: "Shipping containers?", Mr Yusuf replied: "They're not shipping containers, they're purpose-built modular steel structures."
Mr Yusuf claimed British people are being "subjected to the Afghanistan culture" as he defended his party's stance on deportations.
Appearing on Sky News, Zia Yusuf was pressed by presenter Trevor Phillips over Nigel Farage's suggestion that women could be deported back to the Taliban-ruled country.
Mr Phillips asked: "Farage said you would deport women back to Afghanistan.
"They could justifiably claim a fear of persecution. Would you send women back to Afghanistan?"
Mr Yusuf replied: "Why were the Tories OK with thousands of military-age men from Afghanistan? That's why mothers were protesting in Epping - because it was British women that were subjected to that very culture.
"You just laid out the Afghanistan culture that British people are being subjected to."
Conservative Party chairman Kevin Hollinrake accused Reform UK of copying the former Government's migration policies.
Speaking on Sky News, Mr Hollinrake said: "All Reform are doing now - a few weeks ago they were talking about towing the boats back to France and they realised they couldn't do that.
"And all their plans now are a copycat - exactly the plans that we had in the last government.
"We tried to get through - eventually got past Parliament in passing the Rwanda Act - to return people to their own country and if that could not happen to a third country, Rwanda.
"We got huge criticism for it - and Reform are now copying those plans."
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