A new row has broken out over how much the government's controversial identity card plans could cost taxpayers.
MPs and peers are still worried about possible cost overruns
Academics at the London School of Economics (LSE) last year suggested the scheme could cost up to £19bn.
Home Office Minister Andy Burnham, who cannot give a cost estimate, says the LSE now says its figures were wrong.
One of the authors of the LSE report says some parts of its estimates should be cut but argues new costs could push the overall price even higher.
The Home Office says the cards will cost the department £584m but has not given figures for government as a whole.
People will pay £30 for a stand-alone identity card, it says. And it will cost £93 to produce a combined biometric passport and identity card.
The LSE figures would mean the cards would cost £170 to £300 each to produce - although the price paid directly by public might be different.
Mr Burnham said a report from accountants KPMG had concluded the government's estimates were "robust".
And he said some critics were making "wild claims" about costs to damage the principles of the identity card scheme.
Mr Burnham told the BBC News website one of LSE report's authors, Simon Davies, had admitted in a debate with him last week that his figures might need to be downgraded.
He accused the LSE of "shifting its ground" on the costs and said he was convinced the benefits of the scheme would outweigh the costs.
Mr Davies said: "We acknowledged that we will reduce some of the nine items in our costings on the basis of Home Office figures.
"But we also said that we are now going to incorporate the full range of integration costs throughout the public sector."
That means the LSE will now include costs such as other departments matching their computer systems to the new database.
"At best, the outcome will be a zero-sum equation, at worst it will be a higher figure than our original," said Mr Davies.
He said despite the "vitriol" used by ministers against the LSE authors, they had now been proved right.
The government had now "at the 11th hour" admitted the costs for the Home Office were a "microcosm" for those across government, he said.
The Home Office says it will be up to other departments to decide how to use the ID card system.
It says it cannot give cost figures for other departments - but says it is only the Home Office figures which affect the price of the ID card scheme.
Mr Davies countered that the costs would fall to the taxpayer either way. MPs and peers are continuing to raise concerns about the costs.
Former Treasury Minister Lord Barnett said: "The figures at the moment are simply not credible."
And Labour MP John Smith, a self-confessed "serial loyalist", said the plans were "unnecessary, unworkable, costly and ineffective".
"If someone like me is losing confidence than the government has a job on its hand to win us back," he said.
In a Lords debate earlier this week, former Home Secretary Lord Waddington said: "Surely parliament is entitled to know the total cost, which of course includes the cost to other departments who are going to use the scheme."
Home Office Minister Baroness Scotland said she could not give the figures.
But she said ID cards could save the government between £310m and £575m in preventing fraud; between £30m and £40m in immigration control; and between £45m and £85m in reducing the cost of crime.