Thousands of DNA samples from innocent people are now retained.
The government has been defeated in the House of Lords over the issue of keeping people's DNA and fingerprints on the police national database.
Peers backed a Tory amendment calling for specific guidelines to help people seeking to have their details removed from the database by 161 votes to 150
But ministers are unlikely to redraft the legislation, arguing that existing public safeguards will be sufficient.
The defeat is the latest inflicted by peers on the counter-terrorism bill.
Last month, the House of Lords overwhelmingly rejected the government's call for the length of time terrorist suspects could be held without charge to be extended from 28 to 42 days.
The UK has the largest police DNA database in the world - with more than four million people on file.
Under current laws, the database holds DNA records from suspects arrested in England and Wales, regardless of whether they are subsequently charged or convicted.
And innocent people who volunteer to give a DNA sample during a police inquiry also have their details kept on record.
The Home Office argues the database helps to secure convictions for a range of violent crimes, often many years after they are committed.
In Tuesday's debate, security minister Lord West said adequate safeguards already existed to protect the public, as chief police officers had the discretion to delete information from the database in "exceptional cases" after a request is made.
But critics point out that, under the government's proposed guidance, such cases will be extremely rare.
The Conservatives described one example in which details might be destroyed - when the residents of a building in which an apparent murder is committed have samples taken but then it is concluded the death occurred by natural causes - as "laughable".
Peers backed a call for the government to publish new guidelines for procedures enabling people to discover what information is held on them and their family and how they can seek to have it removed.
These would also require the police to explain to people why information should not be removed in individual cases.
Baroness Hanham, the Conservative home affairs spokesman who drafted the amendment, said it should be made much easier for anyone to question why their details were listed on the database.
"What we are looking for is statutory guidelines," she said.
The Home Office said it would produce "appropriate national guidance" on how the police handle and retain DNA information.
But a spokesman said ministers did not plan to change the provisions of the bill to reflect the amendment when it returns to the Commons.
Civil liberties groups welcomed the outcome of the vote, arguing that the retention of DNA was "out of control".
"If the government wants a universal DNA database it should say so, not smuggle one in through the backdoor," Shami Chakrabarti, director of Liberty, said.
Ministers believe such guidelines could hinder their plans for a counter-terrorist database as releasing details of material obtained covertly, through surveillance, could be dangerous.
Before 2001, the police could take DNA samples during investigations, but had to destroy the records if the person was acquitted or charges were not proceeded with.
But the law was changed in 2001 to remove this requirement, and changed again in 2004 so DNA samples could be taken from anyone arrested for a recordable offence and detained in a police station.
The database also contains profiles from some people detained in Northern Ireland, and in Scotland - but in Scotland records of those innocent of any crime are deleted after a time.
A study published earlier this year concluded that guilty people who have served their time should eventually have their DNA records erased because retaining the profile "continues to criminalise them".