The UK's ID card scheme may have to be delayed, the government has admitted.
The laws needed to introduce ID cards were passed this year
The Home Office said the 2008 launch date may change, following a review of the department ordered by the new Home Secretary John Reid.
Mr Reid later told MPs he was still committed to introducing the cards "as rapidly as possible".
The process of putting contracts to establish the scheme out to tender - which software suppliers expected in March - has been put back indefinitely.
Tony Blair says ID cards are needed to tackle terror and illegal immigration. The Conservatives and Liberal Democrats oppose the scheme.
The latest news comes after leaked e-mails disclosed that civil servants had serious doubts about whether the scheme could be delivered.
The government had originally said it would phase in ID cards from 2008.
But a Home Office spokesman told the BBC: "We set a timetable for when ID cards would be introduced and that might change.
"That is dependent on the review that the home secretary is carrying out."
He added: "As part of the Home Office review we are ensuring that the sequencing of our plans is coherent and addresses the priorities of British citizens as the home secretary has identified.
"We have always made clear that its introduction (ID cards) would be in stages - an incremental process. That remains the process."
'Face saving exercise'?
The spokesman said there had been no date set for when contracts to set up the system would go out to tender but added: "There may have been an expectation they would go out to tender when the Bill was published, but we have said it will go out to tender when it was ready. We have not set a timetable."
Computer Weekly magazine says software suppliers expected the tender process to take place last March.
The leaked documents, published by the Sunday Times, suggested the ID card plan could be scaled down as part of a "face saving exercise" so they could still start to be phased in from 2008.
The leaked e-mails quote officials saying ministers were setting themselves up for failure and were "ignoring reality" by pressing ahead.
Conservative home affairs spokesman David Davis said: "This ID card project continues to crumble as doubts about its effectiveness, technology and cost pile up.
"It is becoming ever clearer, even from the government's own perspective, that they should abandon this expensive plastic poll tax which, far from improving our security, may well make it worse."
For the Lib Dems Nick Clegg said the admission of the delay was the "first outward sign of chaos that is engulfing Tony Blair's harebrained ID card scheme".
"John Reid should now come clean. It is only a matter of time before he realises that plans for such a vast identity database are not only flawed in principle but unworkable in practice," the home affairs spokesman added.
SNP spokesman Stewart Hosie MP said the government had failed to make a case for ID cards being able to combat crime, identity theft, terrorism, benefit fraud and unauthorised working.
Phil Booth of campaign group on N02ID said the Home Office was spending £63,000 per day of taxpayers' money to "come up with ever more elaborate excuses for this scheme".