Biometric technology, such as fingerprint and iris recognition, raises issues for people with various disabilities, the BCS said.
This also means the initiative risks falling into the trap of focusing on the technology rather than the user - a well-known cause of problems in some computing projects.
"Many people, especially those with cerebral palsy, have little control of their muscle movement and will find it very difficult to hold their head or finger still long enough for an iris or fingerprint recognition device," said Brian Layzell, chairman of the BCS Disability Group.
"In addition, the lack of control means their hands and fingers are sometimes bandaged because they injure themselves.
"Blind people also face the problem of focusing their eye in the right place for an iris scanner. This means iris recognition units might need some form of audio device to help people line their eyes up to the unit properly."
The positioning of recognition devices and card readers also needs careful thought to cater for people in wheelchairs or with other restrictions, Layzell said.
"Wheelchair users will have trouble if a reading device is at conventional counter height, for example. Similar problems could be faced by people affected by thalidomide, who sometimes have very short arms."
Layzell also pointed to a recognised issue in computing projects: the temptation to be seduced by technology at the expense of practical considerations.
"There is much talk in the ID card proposals about using the latest biometric technology to crack a security problem, but in doing so the technology is throwing up new problems for a significant percentage of the population," he said.
"In the wider debate about proving personal identity there is a need for focused thinking about how usable or otherwise the proposed technology will be for many hundreds of thousands of members of society."
Layzell is being consulted by the Home Office on these issues, and he recommended that specialist university researchers and companies which develop technology to support disabled people should also be involved.
The BCS has said that disabled people and those who cannot handle the complexities of an ID card for other reasons are not catered for in the draft bill.
"These people need to be recognised," the BCS said. "They may have a carer or legal attorney handling their affairs.
"It would seem sensible to allow a nominated carer or legal representative to act for an individual in some carefully controlled circumstances. However, the way the draft bill is currently worded, this appears to be illegal."