The Home Secretary David Blunkett, used a keynote speech at the Institute for Public Policy research to defend the government's plans to spend more than £3.1bn on its national biometric ID card programme.
Blunkett, said that ID cards would only add a small amount to the cost of projects already underway to develop biometric passports - money that would have to be spent anyway to meet international obligations.
His comments were designed to rebut critics who claim that the Home Office has failed to establish a clear business case for biometric ID cards, which are due to be phased to the population from 2007.
"If we are going to incur the cost of setting up a biometric passport," he said, "doesn't it make sense to pay a little extra to have a serious biometric database and have an additional ID card."
The health service was already working on ways to integrate ID cards into its IT systems to allow doctors to check the eligibility of patients for treatment when they register, Blunkett revealed.
The Home Office has made significant changes to the programme following a critical report from the Home Affairs select committee, Blunkett said.
They include making the purpose of the ID card programme clear on the ID card bill, expected to be unveiled in the Queen's speech.
"We have agreed to widen the scope of the surveillance commissioner and individuals will be able to check what information is held on them and who has access data to check their identity," he said.