Asylum seeking migrants could be processed on disused ferries moored off the coast, according to reports.
The suggestion came after it was also claimed that the UK was considering sending migrants to centres in Papua New Guinea, Moldova or Morocco, in suggestions dubbed “bizarre” by a Conservative backbencher.
Government sources refused to be drawn on the reports, stating that the UK was examining how other nations handled migrants with a view to “informing” the British situation.
According to The Times, Number 10 is considering buying retired ferries and converting the vessels into processing centres to house asylum seekers off the UK coast.
The newspaper also stated the Home Office discussed moving migrants to decommissioned oil platforms in the North Sea for processing, but the idea was rejected.
In a version of the Australian “offshore” model, asylum seekers could also be sent to detention centres in Papua New Guinea, Moldova, or Morocco, The Guardian said.
It claimed leaked documents had revealed Downing Street had asked officials to look into the matter, but met “push back” from the Foreign, Commonwealth and Development Office.
Placing migrants on ships is seen as “more realistic” and is an option to be put to Prime Minister Boris Johnson, according to reports.
Adam Holloway, the Tory MP for Gravesham, said it was “completely right” for the Home Office to look at ways of deterring asylum seekers from coming to the UK but called for any solution to be “civilised”.
Speaking to BBC Radio 4’s Today programme, he said: “Talk of oil rigs and Moldova and Papua New Guinea, to me, is somewhat bizarre.
“You’re determined for me to say it is a great idea to put people on islands – I’m not saying that.
“The Home Office is completely right to look at other options so there is some sort of deterrent, but not the Australian model where you have poor welfare standards and everything else.
“We’ve got to find a civilised version of that.”
David Wood, head of enforcement at the Home Office between 2013 and 2015, said overseas processing of asylum applicants was likely to be expensive and unworkable.
He told the Today programme: “I think it is a non-starter.
“The cost of it of course would be enormous and presumably you’d have to have Home Office staff there to process.
“It would be a complete legal, operational and practical impossibility.”
The latest reports follow controversy over a proposal discussed in the Home Office that asylum seekers could be processed on Ascension Island in the South Atlantic.
The option came as a surprise to inhabitants on the volcanic territory 4,000 miles from the UK.
The idea considered within Priti Patel’s department that asylum seekers could be transferred to the British overseas territory in the South Atlantic has been derided as “inhumane” by critics at home.
But it was also dismissed on Wednesday as an unfeasible, “logistical nightmare” by a member of the Ascension Island Council, Alan Nicholls.
Shadow home secretary Nick Thomas-Symonds said: “This ludicrous idea is inhumane, completely impractical and wildly expensive. So it seems entirely plausible this Tory Government came up with it.”
Ms Patel has vowed to stop migrants making the perilous journey across the English Channel in small boats amid record numbers of crossings.
The proposal further reflects the influence of Australia – which has controversially used offshore processing and detention centres for asylum seekers since the 1980s – on the UK’s immigration and asylum policy.
The Government has based its post-Brexit points-based immigration system on that developed in Australia.