The immigration minister has suggested it could be weeks before the migrants are transferred back to the barge Bibby Stockholm.
Robert Jenrick told MPs that the asylum seekers would be transferred back to the barge in Dorset “as soon as possible” provided security checks showed no “cause for concern” and he expected this to happen “within weeks”.
His comments came as figures showed new cases of diphtheria among asylum seekers in England were reported for the first time since January and crossings across the Channel continued for a fourth straight day.
The first asylum seekers arrived on the Bibby barge last month but were turned away again days later after tests revealed they had Legionella – the bacteria that can cause the potentially fatal Legionnaires' disease.
Since then, ministers and officials have been unable to say when the migrants would return to the ship.
Home Secretary Suella Braverman insisted the giant vessel is safe amid threats of legal action from firefighters.
Conservative MP Richard Drax, whose South Dorset constituency is home to the barge, asked in the Commons on Tuesday “when and if” the migrants would return.
Mr Jenrick replied: “It was very unfortunate that the emigrants had to be removed from the barge during the summer. We deeply regret this. We took a very proactive approach.
“Tests have subsequently been conducted and definitive answers to these tests will be received very soon.
“Assuming they show no signs of Legionella or indeed any other bacteria or cause for concern, then we will get people back on board as soon as possible. I think we can expect it within weeks.”
Labour's shadow immigration minister, Stephen Kinnock, said: “Bibby Stockholm was supposed to be a symbol of Tory cuts to asylum spending, but the minister didn't even mention that spending today.
“Instead it stands alongside the boats and hotels as a floating symbol of Conservative failure and incompetence, costing the taxpayer half a million pounds a month.”
It comes as figures from the UK Health Safety Agency (UKHSA) showed that three cases of diphtheria among asylum seekers were reported in England in August, bringing the total number of cases for 2022 and 2023 to 77.
The total previously rose to 74 after a case was reported in January. No further cases were reported between February and July, the data show.
The Home Office refused to confirm whether any of the latest cases were traced to people at Bibby Stockholm or those staying at the former RAF Wethersfield air base in Essex, which first opened to migrants in July, when asked by its news PA agency.
Fifty-five of the cases have been recorded in the South East, seven in London and there were fewer than five in each of the following regions: East of England, West Midlands, South West, North East, North West and Yorkshire and the Humber, the latest report said. but a county-by-county breakdown is not provided.
A spokeswoman for the department said: “The health and welfare of asylum seekers in our care is of the utmost importance. There have been a very small number of cases of diphtheria and all individuals have been treated.
“The Home Office is contacting the UKHSA about suspected cases of diphtheria and infections. This may include the safe movement of people to more appropriate accommodation to support their safe isolation.”
Asylum seekers with symptoms of the highly contagious disease were placed in isolation last year amid a rise in the number of infections among people arriving in the UK.
However, health ministers and officials have insisted that the risk of the public contracting diphtheria is very low and infections are rare.
At the time, Ms Braverman faced criticism for overcrowding and disease outbreaks at Manston amid concerns that a man held there may have died from a diphtheria infection.
Since the beginning of September, 1,271 migrants have been spotted crossing the Channel, according to Home Office figures.
Pictures showed groups of men being carried ashore on Tuesday amid warm, dry and calm sea conditions before boarding a coach to be taken away from a Border Force compound in Dover, Kent.
On Monday, 286 people made the trip on five boats, bringing the provisional total for the year so far to 21,372.
In the Commons, the immigration secretary insisted that “our plan is the most comprehensive of any strategy to tackle this problem in Europe”, adding: “And it shows. As of today, arrivals are down 20% compared to last year and for the month of August, the drop was over a third.”
But Mr Kinnock said: “The only reason the number is not breaking last year's record is because of the bad weather in July and August. And a strategy that depends on the weather is probably not a very sustainable strategy.”
Mr Jenrick also insisted the government was “on track” to clear the backlog of 92,601 so-called “legacies” in the system since the end of June last year – after Rishi Sunak set a target of doing so by the end of 2023 .
Separate figures show there has been a sharp increase in the number of staff working to clear the backlog. The number of full-time equivalent roles rose from 1,729 on 31 July to 2,445 on 31 August – a 41% jump.
But Mr Kinnock branded the legacy backlog “a figment of the Prime Minister's imagination”, adding: “The only backlog that matters is the 175,000 people (waiting for an initial decision on their application) and that's still growing and we know that the government is cooking the books in this regard, making large numbers of asylum-seekers turn away because they missed a single appointment or did not fill in a form correctly.”