Race discrimination could be worsened by the introduction of a national UK identity card, a committee of MPs has been told.
A compulsory ID card is unlikely for some years
Shami Chakrabarti, Liberty's director, told them: "We believe that problem will be infinitely compounded by the creation of a single compulsory card."
Plans for an identity card system were unveiled in last year's Queen's Speech.
Information Commissioner Richard Thomas said only "the absolute minimum" information should appear on the card.
Ms Chakrabarti and Mr Thomas were giving evidence to the Commons home affairs committee, which is looking into the ID card proposals.
The probe follows the start of a six month trial, which began in January, on the technology to be used for the cards, with 10,000 volunteers having their fingerprints or iris scans put on cards.
The scheme will be rolled out through passports and driving licences - but a decision on whether to make the cards compulsory will not come until 2013.
Liberty is opposed to the measures, claiming a number of means of identification, such as a passport, driving licence or benefit card, was still the safest option.
Ms Chakrabarti said she had "immediate concerns" about how an ID card would impact on race relations in particular.
She told committee chairman John Denham: "This particular scheme is flagged as partly a solution to concerns of illegal immigration, which in itself means that such a card is going to be demanded with respect of people like me, rather than people like you.
"There is inherent discrimination in the scheme because it's going to become compulsory for foreign nationals before it becomes compulsory for British nationals."
She said statistics already showed that a young black male is eight times more likely to be stopped and searched than a white male.
"We believe that problem will be infinitely compounded by the creation of a single compulsory card .... This is born out by the comparative experience of other European countries where such cards have been used - France, Germany and Portugal in particular."
Ms Chakrabarti said she accepted that boarding a trans-Atlantic flight was a time when the production of identity was justified, but she insisted a single ID card raised privacy issues.
Abuse of power?
"To create a single national compulsory identifier ... creates a shift in the relationship between the individual and the state, so in fact you are required to identify yourself, to be called to account ... whether it is justified or not."
Vicky Chapman, from the Law Society, told MPs she did not believe the government had made the case for a compulsory card. "It's a little unclear to try to understand what is actually being proposed," she said.
Richard Davies, from the global watchdog Privacy International, said public opposition for an ID card in Australia shifted from 10% to 90% during a campaign in 1987.
"It didn't take much to persuade the entire Australian population," he said.
"All you need to do is present people evidence of the way authorities can abuse power," he said, adding that he believed the UK card would breach the European Convention on Human Rights.