ID cards are being introduced from this year
Identity cards could be handed out to children as young as 14, a home office minister has suggested.
The first ID cards are due to be offered to 16 and 17-year-olds from 2010 as part of a plan to introduce the controversial scheme in stages.
But Meg Hillier said the age range was still "up for grabs" and could be lowered "if they prove popular".
She also said the scheme might be too far advanced for the Tories to "unpick" if they came to power in 2010.
Speaking at a "No ID, No Sale" fringe meeting at the Labour Party conference, Ms Hillier said a ministerial working party was considering extending the scheme to younger children and was talking to the universities and youth groups about the idea.
She said she had been "struck" by a visit to Hungary, where 14-year-olds routinely carried ID cards - and she pointed out that six-year-olds were already fingerprinted for visas.
'Full steam ahead'
The Conservatives and Lib Dems have both said they would scrap the ID card scheme, which they say will cost too much and threatens civil liberties.
But Ms Hillier said the Tories would find it difficult to "devalidate" the cards that had already been issued and scrap the database that was also being used for passports.
"There isn't an easy way to unpick this scheme, quite rightly because it is invaluable."
She also hit back at suggestions by anti-ID card campaigners that the scheme might not go ahead.
"it is full steam ahead," she told the meeting, "in fact the prime minister wanted me to do it quicker than it was possible."
She said, at £30, the cards would be cheaper than passports, which they would probably replace passports altogether at some point in the future.
James Lowman, of the Association of Convenience Stores, said his organisation backed ID cards but wanted government to take the lead in changing the culture so that people would get used to being asked to prove their age.
At the moment, shop workers were being abused and assaulted when they asked for ID from young people trying to buy cigarettes, alcohol, solvents and other age-restricted products, he told the meeting.
Chris Ogden, of the Tobacco Manufacturers' Association, which represents the big cigarette firms, also backed ID cards but said it would persist with its own proof-of-age scheme "until such time as a national identity card is introduced".
Ms Hillier said she would be speaking to the retailers' trade association about ways of helping customers get used to producing their ID cards as proof of age in shops, although she stressed it was "not the primary function" of ID cards.
She doubted whether the UK would ever have a "proof of age" culture similar to the United States, which "dates back to prohibition".
Phil Booth of No2ID said Ms Hiller was "delusional" if she thought ID cards could not be scrapped by an incoming Conservative government.
"The officials themselves, since 2006 have designed the contract on the basis that the entire scheme could be canned at the next election."
"It could simply be downgraded so it is just for passports," he told the BBC News website.
Mr Booth, who had been due to speak at the fringe meeting but was unable to gain entry to the conference centre because of a problem with his pass application, also criticised the plan to give the cards to younger children.
He said ID cards legislation specified a minimum age of 16 and he said it was wrong for young people to be tied into a giant database "for the rest of their lives".
On his conference pass problems, he said: "If this is how they are organising their ID for their own party conference, how the heck are they going to organise ID cards for 50 million people?"