Up to £74 million has been spent in the last five years funding a voluntary return scheme for those who have no right to remain in the UK.
The programme currently offers packages worth up to £2,000 “in kind” support in their home country in return for them not fighting removal.
It comes a week after The Daily Telegraph disclosed that up to £25 million has been spent over the same period in “bribes” for foreign criminals to go home.
Separate figures today also show that a further £8.2 million was spent last year on charter flights to send almost 2,000 failed asylum seekers and foreign prisoners home.
Ministers insist the expenditure saves the taxpayer in the long run because it saves on lengthy legal battles to avoid removal.
But the rising public bill has renewed the debate over where the line should be drawn.
James Clappison, a Tory MP and member of the Commons home affairs select committee, said: “This is one symptom of the legal mess we face in the whole asylum system.
“We need to see a review of it so as to facilitate the easier return of asylum seekers whose claims fail.”
The assisted voluntary return programme provides support for those who are willing to return home without appealing against removal.
Packages are currently worth up to £2,000, most of which is “in kind” support such as help setting up home or a business.
In 2007 it emerged the packages had been used to help set up an ostrich farm in Iran and a vineyard in Albania.
The Coalition faced criticism in March when it emerged it was offering those with no right to be in the country a secondary bribe to take up the offer.
Immigration rules were changed so that those who accept a returns package could apply to come back to the UK after just two years instead of the previous five year bar.
The change does not mean an individual will definitely be admitted back in to the UK but it means the time they have to wait before reapplying has more than halved.
Since 2006, a total of £73.9 million has been spent on the voluntary return scheme–the equivalent of £1.2 million a month.
The National Audit Office has previously estimated it costs £11,000 on average to deport a foreign national who refuses to leave.
Damian Green, the immigration minister, said: “Assisted Voluntary Returns represent good value–they cost less than an enforced return and save the taxpayer money by reducing the amount spent on financial support and detention.
“We’re determined to ensure that those who do not need our protection, and those who come here to play the system, are sent home as quickly as possible.”
Separate figures obtained by this newspaper show that £8.2 million was spent in the last year on 53 charter flights to remove failed asylum seekers and foreign prisoners.
Charter flights often have to be used because those facing removal can create disturbances on regular scheduled flights which usually results in them having to be taken off the plane.
The flights last year removed 1,200 failed asylum seekers and around 480 foreign national prisoners, meaning it cost the taxpayer the equivalent of £4,880 per removal.
Mr Green added: “We will do all we can to ensure those with no right to be in the UK are removed as soon as possible, including using charter flights when it is cost effective to do so.
“Charter flights save the taxpayer money by reducing the amount spent on financial support and detention.”