Ministers are being sent on a "charm offensive" tour to educate the public about the technology behind planned ID cards, the Home Office has said.
Home Office minister Andy Burnham opens the seven-date "biometric roadshow" tour at Manchester airport on Monday.
He hopes the tour will help persuade people identity cards would protect their "personal data and privacy".
Civil rights group Liberty called it "yet another desperate attempt to sell Tony Blair's £10bn white elephant".
Director Shami Chakrabarti said: "In this world, black is white, night is day, and Mr Burnham says ID cards will protect our civil liberties.
"Enough is enough.
"This money should be reallocated to policing and national security."
Mr Burnham said the government was working hard to keep down the cost of the cards.
He denied reports the price of a card had spiralled to £300.
"I'm one of the staunchest supporters of ID cards yet I wouldn't pay £300 for one," he told the News of the World newspaper.
"And if the cards were to cost £100, as some claim, my Lancashire constituents in Leigh would have a few choice words for me."
The fact it will not be compulsory to carry them should calm fears the cards would create a "Big Brother" state, Mr Burnham added.
Subtle claims
"Our plans for biometric ID cards are controversial to some.
"They have whipped up fears that ID cards will create a police state.
"These myths are easy to knock down.
"But we have been slower to respond to more subtle claims that ID cards weaken the privacy of the individual against the state.
Proud statement
"In fact, the exact opposite is true.
"It may sound like a bold claim but our ID card system will protect personal data and privacy."
A Home Office spokeswoman told BBC News it would initially become compulsory to register for the planned cards when applying for "designated documents", including passports.
A card would also be a "recognised travel document" allowing travellers to go anywhere within the EU without their passports, she added.
The planned cards would contain a microchip carrying biometric information - a person's fingerprints or iris or facial scans, which are unique to the individual.
The biometric details are designed to make the cards more difficult to forge but critics say they are not foolproof and may be more difficult for some groups, such as disabled people, to use.
Mr Burnham also hopes the cards will display a Union Jack as a "proud statement" of British identity.
Home Office minister Andy Burnham opens the seven-date "biometric roadshow" tour at Manchester airport on Monday.
He hopes the tour will help persuade people identity cards would protect their "personal data and privacy".
Civil rights group Liberty called it "yet another desperate attempt to sell Tony Blair's £10bn white elephant".
Director Shami Chakrabarti said: "In this world, black is white, night is day, and Mr Burnham says ID cards will protect our civil liberties.
"Enough is enough.
"This money should be reallocated to policing and national security."
Mr Burnham said the government was working hard to keep down the cost of the cards.
He denied reports the price of a card had spiralled to £300.
"I'm one of the staunchest supporters of ID cards yet I wouldn't pay £300 for one," he told the News of the World newspaper.
"And if the cards were to cost £100, as some claim, my Lancashire constituents in Leigh would have a few choice words for me."
The fact it will not be compulsory to carry them should calm fears the cards would create a "Big Brother" state, Mr Burnham added.
Subtle claims
"Our plans for biometric ID cards are controversial to some.
"They have whipped up fears that ID cards will create a police state.
"These myths are easy to knock down.
"But we have been slower to respond to more subtle claims that ID cards weaken the privacy of the individual against the state.
Proud statement
"In fact, the exact opposite is true.
"It may sound like a bold claim but our ID card system will protect personal data and privacy."
A Home Office spokeswoman told BBC News it would initially become compulsory to register for the planned cards when applying for "designated documents", including passports.
A card would also be a "recognised travel document" allowing travellers to go anywhere within the EU without their passports, she added.
The planned cards would contain a microchip carrying biometric information - a person's fingerprints or iris or facial scans, which are unique to the individual.
The biometric details are designed to make the cards more difficult to forge but critics say they are not foolproof and may be more difficult for some groups, such as disabled people, to use.
Mr Burnham also hopes the cards will display a Union Jack as a "proud statement" of British identity.