There is growing unease about the need for a national ID card, said Simon Davies of the civil liberties group Privacy International.
The organisation is holding the first public meeting about the controversial plans in London on Wednesday.
"The scheme will form the basis for matching of personal information between government and private sector organisations and will involve a legal requirement to produce the card in a wide variety of circumstance," Mr Davies told BBC News Online.
Lively debate
In July, the government announced a six-month public consultation on proposals to establish a national identity card to confirm entitlement to benefits such as healthcare, welfare, education and public housing.
The ID card is likely to be backed up with a national database of biometric information such as digital photographs, fingerprints and retina scans.
Speakers at the public debate will include the Minister for State for Criminal Justice Lord Falconer QC, Head of the Entitlement Cards Unit at the Home Office Stephen Harrison and Peter Lilley, former secretary of state for social security.
It is thought that dozens of key organisations will attend the meeting. Mr Davies believes the debate is crucial.
"Until now government ministers have stayed silent on the proposals. They have offered nothing concrete to spark public debate," he said.
"Failure to disclose your card may result in denial of access to a wide range of essential services such as healthcare and education," he added.
The meeting is due to be held on 11 December at the London School of Economics.