Proposals for ID cards should be published within a month, David Blunkett has told BBC Radio 5 Live.
The speed of progress will take many by surprise
The home secretary said an agreement had been hammered out among top Labour politicians despite some "misgivings".
On Sunday Trade Secretary Patricia Hewitt said there had to be evidence that making ID cards compulsory had "additional benefits".
"We are going to publish a draft bill, hopefully, in the next four weeks," Mr Blunkett said.
He added: "It would be very surprising if there were not misgivings."
Last week Tony Blair said at his monthly news conference that identity cards would be introduced "more quickly than even we anticipated".
He said that the government had won over those who opposed the controversial measure for civil liberties reasons.
Practical issues and logistics were the only things stopping the introduction of ID cards, he said.
His official spokesman later expanded on the comments saying Mr Blair recognised there was an issue here "which we are addressing and do need to address in the light of outrages such as Madrid and the threat posed to this country".
He added: "That is why the issue was placed on the agenda in November and is being addressed in the way it is."
Labour backbencher Austin Mitchell said ID cards were "not going to be an answer to terrorism" adding there was "a lot of discontent" on the government benches over the issue.
"I don't think the practical side has been really thought through ... the devil is in the detail, not in the principle," he told BBC Radio 4's World at One programme.
Last week Britain's top police officer backed calls for the quick introduction of ID cards and criticised Ms Hewitt for saying it will take "many years" to introduce ID cards, branding her "wrong".
In his interview Metropolitan Police commissioner Sir John Stevens said: "Up to a year and a half ago I would have been against identification cards because we had no certainty that the documentation used for identification cards could actually prove with certainty the identification of someone.
"Biometrics, the use of eyes, the use of fingerprints is now a certainty in a way that never was before so therefore identification either whether it be on border controls or whether we have to deal with stop and search in the street, anti-terrorism kind of activity or even along the normal way that police officers work would give a certainty we need."
On Ms Hewitt's remarks about ID cards he said he "disagreed totally" with the trade secretary, adding that the sooner the legislation was passed the better.