A broad catch-all discretion enabling police to keep the DNA of innocent people indefinitely for reasons of national security should be scrapped, MPs and peers have said.
Ministers have failed to provide a justification of why this power is necessary and proportionate, the Joint Committee on Human Rights (JCHR) said.
Its report on the Protection of Freedoms Bill, which is due to go through its remaining stages in the Commons next week, said the proposals regarding the retention of DNA should be reconsidered.
Home Secretary Theresa May has said the plans to curb the state's right to intrude in private lives would see almost one million innocent people have their names removed from the national DNA database.
Under the Government's plans only adults convicted or cautioned will have their DNA stored indefinitely, while those charged but later cleared will see their profile stored for up to five years. But the committee warned this would create "a significant risk of incompatibility with the right to a private life" and called for further evidence to prove it was justifiable.
The Bill would also "create a broad 'catch-all' discretion for the police to authorise the retention of material indefinitely for reasons of national security", the committee warned.
"We are concerned that the minister has not provided a justification of why this power is necessary and proportionate, particularly in light of specific measures targeted towards retention in relation to counter-terrorism and immigration," the report said.
"Without further justification or additional safeguards, these measures should be removed from the Bill."
A Home Office spokesman said: "National security is the first duty of any government. Where DNA needs to be retained on national security grounds it will have to be approved by the independent Biometric Commissioner, which will provide a strong safeguard.
"The last government kept the DNA of innocent people, but didn't even bother taking it from prisoners. We're going to take samples from the guilty and get rid of them when people have done nothing wrong."