Theresa May suppressed a Home Office report that found changes to the DNA database would make it harder to catch murderers and rapists, according to Labour.
The House of Commons is expected to pass the Protection of Freedom Bill on Monday. Under government's plans only adults convicted or cautioned will have their DNA stored indefinitely. Those charged but eventually cleared will see their DNA stored for up to five years.
But Labour have said unpublished Home Office research showed that 23,000 people every year, who under Labour’s system would be on the DNA database but under government plans will not be, will commit further offences.
Labour also say the report showed 6,000 of those a year will go on to commit crimes including rape, murder and manslaughter.
The analysis of the Home Office report was conducted by the House of Commons library for shadow home secretary Yvette Cooper.
She said the initial report was given to crime minister James Brokenshire by officials in July 2010, but ministers then chose not to publish its findings.
Cooper said May was taking "unacceptable risks with public safety" by ignoring the evidence provided by her own department.
“The home secretary is making it harder for the police to catch criminals and cut crime. It is shocking that 23,000 fewer criminals each year will be on the DNA database -- making it harder for the police to catch offenders. And it is outrageous that Ministers have hidden these figures from the public, the police and parliament.
“These figures mean 6,000 fewer serious offenders, including murderers and rapists will be on the DNA database -- making it harder to catch them or deliver justice for victims.
“It is incredible that Theresa May has not only ignored her own department's research but kept it from the public and from the home affairs select committee. Policy on DNA should be based on evidence not political rhetoric.
“The Home secretary seems hell bent on weakening the ability of the police to fight crime. Whether it’s cuts to police officers, weakening the DNA database or the ability to use CCTV she is taking unacceptable risks with public safety and it will be communities that suffer as a result.”
The government has rigorously defended its changes to the DNA database on civil liberties as well as practical policing grounds.
The home secretary told the Commons in May: "The police national DNA database, which was established in 1995, has clearly led to a great many criminals being convicted who otherwise would not have been caught."
"However, in a democracy, there must be limits to any such form of police power. Storing the DNA and fingerprints of more than a million innocent people indefinitely only undermines public trust in policing. We will take innocent people off."
The government has also been accused of not going far enough in safeguarding the public's right to privacy.
On Friday the parliamentary Joint Committee on Human Rights (JCHR) made up of MPs and peers said the measures that would permit police to hold the DNA profiles of innocent people indefinitely should be removed from the Bill.
"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," its report said.
"Without further justification or additional safeguards, these measures should be removed from the Bill."Suggest a correction