Airport workers are calling for consultation over plans to make them first in line for ID cards.
Unite, the union which represents workers in the civil air transport sector, wants "full consultation" with airport group BAA after it was revealed it is in talks with the Home Office over the plan.
And the union said it wants to make sure workers will not shoulder the projected £93 cost of the biometric card.
BAA confirmed it was talking to the Home Office about airport workers being among those required to have ID cards under the £5.4bn National Identity Register scheme from about 2009.
Brian Boyd, national officer for Unite, said: "We would be seeking assurances that the introduction of ID cards would in no way discriminate against existing or new BAA employees.
"We want the process to be transparent, they [the BAA] would have to be able to substantiate the reason why workers are not able to get employment or an ID card. If the cards are necessary for continued employment at BAA they also need to make sure that the costs do not fall on the employee."
A spokesman for BAA said: "We can confirm that we are in preliminary discussions with the Home Office."
A spokesman for the Identity and Passport Service said it made sense to adopt an incremental approach to rolling out ID cards: "It is obviously right and logical that our first priority should be to consider where ID cards can be of greatest benefit to the security of the UK."
Foreign nationals coming to the UK will be given cards from the end of this year and the Home Office is expected to announce details within weeks of which category of migrants will be required to have a card.
The widespread rollout to UK citizens, known as "Borders phase II", is now slated to begin in 2012; two years later than indicated in an earlier government action plan.
Critics of the scheme said the perceived two-year slip in the widespread rollout of the cards is another sign of wavering support among Gordon Brown's government for ID cards. Doubts in the scheme were further exacerbated by Accenture and BAE Systems pulling out of the procurement process to build the ID card computer system.
Meanwhile the government admitted to another embarrassing data mishap after it revealed a CD containing details of 4,000 offenders the Dutch authorities wanted to trace had been missing for almost a year.