Analysis by Labour is said to have shown that spending on hotels for asylum seekers could rise to more than £4 billion a year.
It comes as the Bill returns to the Commons on Wednesday.
The Home Office is currently spending £6 million per day on hotel accommodation for asylum seekers, a Labour statement said.
Almost 50,000 people are currently in hotels on top of approximately 57,000 in long-standing asylum accommodation.
The Illegal Migration Bill changes the law so that people who arrive after March 7 will still be placed in asylum accommodation, but will not “ever” have their case for asylum assessed, Labour said.
The party added that although Government ministers have promised that people will be removed from the country, Rwanda is expected to take only a couple of hundred people.
According to Government forecasts, around 53,000 people will be subject to the Bill’s provisions this year.
The Home Office is drawing up plans for “huge numbers” of new hotels as well as bases and barges as a result of the Bill, Labour said.
The party added that new asylum hotels have been proposed or opened across the country – including in Hereford, Kegworth and Aberdeen – since the Prime Minister “promised” to end hotel use in December.
Shadow home secretary Yvette Cooper said: “This Bill is going to create even more chaos in the asylum system. Far from ending hotel use, this Bill is going to mean thousands more people in taxpayer funded hotels and accommodation.
“No self-respecting minister who believes they will still be in the job in a year’s time and having to deal with this chaos would stand behind this Bill. They should vote instead for Labour’s plan to fast track decisions and returns to end hotel use.”
Labour is calling on Tory MPs to vote for fast-track asylum decision making and returns for safe countries such as Albania and India to help clear the backlog and end hotel use.
Labour’s claims are laughable and anyone can see through them— Government spokesperson
The party is also demanding Tory MPs back a new requirement for the Home Office to consult local councils on new asylum accommodation and for a duty on the home secretary to deport terrorists who arrive on small boats.
A Government spokesperson said: “Labour don’t want to stop the boats – they want to scrap the Rwanda deal which would increase the costs of our asylum system. Our plan, when in force, would deter people from making the journey in the first place.
“Labour’s claims are laughable and anyone can see through them.”