Shabana Mahmood, the new home secretary, will host a meeting of the Five Eyes security alliance to discuss how to stop people-smuggling as it emerged that ministers were looking at housing those who entered the UK by small boat in military barracks.

Mahmood is to be joined in London by Kristi Noem, the US secretary of state for homeland security, as well as interior ministers from Australia, Canada and New Zealand – the other member countries of the intelligence-sharing pact.

In her first major engagement in the job, she will also host discussions on stopping child sexual abuse online and how to halt the spread of deadly synthetic opioids.

“The Five Eyes might be drawn from different corners of the globe, but we are united by our alliance. As the security threats we all face become more complex and span continents, we are stronger and safer together,” she said.

Mahmood’s biggest challenge in the role will be dealing with the issue of small boats crossing the Channel facilitated by people-smugglers, with almost 1,000 people arriving by that route in order to seek asylum on her first day in office. The issue has caused public frustration, with successive prime ministers promising to “stop the boats” but having little success.

Mahmood said on Sunday that the first returns would begin “imminently” under a deal with France in response to the latest figures.

“These small boats crossings are utterly unacceptable and the vile people smugglers behind them are wreaking havoc on our borders,” she said.

“Thanks to our deal with France, people crossing in small boats can now be detained and removed to France and I expect the first returns to take place imminently.

“Protecting the UK border is my priority as home secretary and I will explore all options to restore order to our immigration system.”

John Healey, the defence secretary, confirmed on Sunday that military sites may be used temporarily as Keir Starmer was “absolutely determined” to end the use of hotels earlier than planned.

He said military planners were looking at possible sites for accommodation on defence bases, as the prime minister wanted to end the use of hotels to house asylum seekers sooner than the promised date of 2029.

Healey told Sky News’s Sunday Morning with Trevor Phillips: “With the Home Office, I have been putting military planners into their border command and into their planning for the future.

“We are looking at the potential use of military and non-military sites for temporary accommodation for the people who come across on these small boats that may not have a right to be here or need to be processed rapidly before we can decide whether or not they should stay or whether or not we deport them, like we have done in record numbers over the last year.”

Speaking later on BBC One’s Sunday with Laura Kuenssberg, Healey was pressed on whether the military could play a bigger role in patrolling the border. He did not give a clear answer but suggested that military bases and help with planning were the extent of the army’s work at the moment.

Starmer has moved to toughen up his policy on the issue of small boats, as Reform UK has a double-digit poll lead and continues to attack the government on its failure to meet its pledge of “smashing the gangs”. There have also been protests outside hotels, including in Epping in Essex, where discontent erupted after the sexual assault of a 14-year-old girl by a man seeking asylum.

This week, Starmer has changed direction by bringing in Mahmood as home secretary, replacing Yvette Cooper. The government is also looking at the idea of trying to change the application of the European convention on human rights’s right to family life in order to enable more deportations of those it believes have no right to be in the UK.

Enver Solomon, the chief executive of the Refugee Council, said: “The answer to failed asylum hotels is not failed asylum camps. The government had rightly begun to move away from using more former military camps after its own spending watchdog found they cost more to run than using hotels and were an expensive failure.

“It’s time for a more pragmatic approach if the broken asylum system is going to be fixed. The solution is faster, fairer decisions and safe housing in communities, so refugees can work, study and rebuild their lives.”

Reform UK said over the weekend at its conference it would stop small boat crossings of people seeking asylum within two weeks of taking office. Nigel Farage clarified on Sunday that he meant he would pass legislation within two weeks to stop judges preventing deportations of those who entered the UK by illegal means.

Zia Yusuf, Reform UK’s head of policy, denied claims that asylum seekers would be housed in shipping containers, saying the party would use “purpose-built modular steel structures”.

Speaking on Sky News on Sunday, 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.”