The Home Office is considering using the former Defence Fire Training and Development Centre in Manston to process asylum seekers, it has been reported.
It was announced last year the centre would close after a 12-year contract - worth £525 million - was agreed to outsource the MOD's fire and rescue to company Capita Business Services.
Training was transferred to a facility already owned by the firm in Moreton-in-Marsh in the Cotswolds.
BBC South East has reported that ministers have been drawing up the plans to deal with the rising number of people crossing the Channel in small boats.
Cadets and reservists based at the site have been told they must vacate the site imminently, according to the report.
It is also understood the site would have its own medical security facilities - and would not be for long-term accommodation.
But it has also been reported North Thanet MP Sir Roger Gale has been seeking "urgent clarification" from the Home Office and MOD.
The BBC say they contacted the Home Office for comment but are yet to receive a response.
It comes after a cross-party group of parliamentarians accused the government of inflicting "profound harm" on people being housed at Napier Barracks.
The former Army accommodation in Folkestone is one of a number of sites being used to house people seeking asylum in Britain who would otherwise be destitute.
A report published last week revealed the All-Party Parliamentary Group on Immigration Detention (APPG) found evidence of "appalling treatment and conditions" at Napier Barracks, Penally Camp in Wales and the Tinsley House Immigration Removal Centre near Gatwick Airport.
The barracks are part of the wider Shorncliffe Army Camp and which previously housed service personnel for short stays.
The site has the capacity to hold 523 people - but the Home Office refuses to say how many people are currently housed there.
Although the Home Office insists individuals are not detained there, the APPG says conditions there – including visible security measures, surveillance and lack of privacy – make it akin to 'quasi-detention'.
In August, Folkestone and Hythe District Council revealed the government was extending its use of Napier until September 2025.