DNA matches from the national database help solve as few as one crime in every 1,300, it was claimed today.
Figures published in a Home Affairs Select Committee report suggest just 3,666 crimes are detected every year with links to an existing DNA profile.
That is one in every 1,300 of the 4.9 million crimes carried out, and just one in 350 of the 1.3 million crimes solved by police.
Senior police officers told the committee that around 33,000 crimes are solved using DNA matches.
But many of those would be solved even without the need for a national database, the report said.
It quotes the 3,666 figure, which was calculated by Genewatch, a pressure group, but warns it is difficult to be sure the figure is accurate.
The report states: "It is currently impossible to say with certainty how many crimes are detected, let alone how many result in convictions, due at least in part to the matching of crime scene DNA to a personal profile already on the database, but it appears it may be as little as 0.3 per cent."
Committee chairman Keith Vaz said: "DNA profiling and matching are vital tools in the fight against crime.
"However, especially in the case of those who are arrested and have their DNA taken but are then never charged, or never convicted of a crime, it is a very complex issue to balance the potential benefit of retaining their data against the threat to individual privacy.
"We do not think we should go back to the situation where DNA is only taken on charge, not arrest, but it is vital that it is made easier for those wrongly arrested or who have volunteered their DNA to get their records removed from the database.
The report said there was a "lack of consistency" in decisions on whether to remove the DNA of innocent people.
Mr Vaz called for a "consistent, fair and prompt" central system to replace individual decisions made by individual Chief Constables.
Critics have claimed there is a "postcode lottery" for decisions, with some forces refusing to remove any records once a case is closed while others deleted them in 80 per cent of request cases.
The MPs said their inquiry was launched amid "growing public concern" over the size of the database, which now holds the profiles of more than 5.5 million people.
Currently genetic profiles from anyone arrested but later released without charge or cleared in court are held indefinitely.
But under proposed laws currently going through Parliament they will be held for up to six years before being deleted, except in terrorism cases.