The government's Identity Cards Bill has been criticised in two separate reports by MPs and Lords over the amount of personal information that would be stored on the National Identity Register (NIR) and the lack of safeguards to protect that data.
The House of Lords all-party Constitution Committee said an independent body is needed to be the "custodian" of the NIR to prevent improper access to data by public servants.
The chairman of the committee, Lord Holme of Cheltenham, said the ID cards bill "fundamentally" alters the relationship between citizens and the state and called for tougher safeguards.
He said in the report: "The Committee firmly rejects government claims that, in respect of privacy, ID cards are comparable to driving licences and passports. Parliament should not allow the Home Secretary such powers to administer this significant and complex scheme."
The committee also said the current bill should only cover the voluntary phase of the scheme; new legislation should be required for any move to make it compulsory for the entire population to register for an ID card.
A separate report out on the same day by the House of Lords and House of Commons joint all-party committee on Human Rights also criticises the ID cards bill and warns that the stated aims of the ID card scheme do not justify the huge invasion of privacy it will cause.
The report said: "The bill's provision for the retention of extensive personal information relating to all or large sections of the population may be insufficiently targeted to be justified as proportionate to the statutory aims."
One concern voiced by the MPs and peers is that the NIR could be used as a tool to track everything an individual does.
It said: "The retention of records of checks against the Register... is likely to build up a comprehensive picture of an individual's employment, use of public services and private transactions, which over time, would amount to a considerable intrusion on the individual's private life."
The report also said the requirement to hand over personal details for the NIR in order to get other documents such as a passport would effectively make the ID card scheme compulsory for large groups of people.
Concerns that there aren't enough safeguards in the ID cards bill to prevent unauthorised disclosure and leaks of personal information from the NIR are also raised in the report.
The bill was narrowly approved by MPs last week in the House of Commons and is due to begin what is expected to be a rocky passage through the House of Lords on 31 October.