Parties dispute each others' interpretation of crime figures
The Tories claim official figures back up its argument that violent crime has risen under Labour, reopening a long-running political row over the issue.
Data from the House of Commons library obtained by the party showed a 44% rise in crimes against the person between 1998 and 2009, the Conservatives said.
Labour maintain violent crime is on a downward trend with half a million fewer victims since it came to power.
The statistics watchdog says parties should not rely on one set of figures.
The UK Statistics Authority, set up by the government to ensure the correct use of figures, has warned that individual crime surveys can appear to produce different results and that politicians should refer to "all available" statistics to presented a "balanced" argument.
The row came as Labour launched a campaign accusing the Tories of being "weak" on crime, saying they would scale back CCTV cameras and make it harder for the police to use DNA to catch criminals.
The Conservatives have long maintained that violent crime has risen under Labour, a claim disputed by ministers with equal vehemence.
The Tories say its case is supported by analysis by the House of Commons library, produced in response to a request by an MP.
This information, obtained by the Conservatives but which they have yet to publish in full, suggests offences against the person rose from 618,417 in 1998 to 887,942 last year.
Shadow home secretary Chris Grayling said this data underlined the "scale of the challenge" facing the police in tackling violent crime.
"This new analysis confirms that the level of violent crime actually reported to police officers in police stations up and down the country is much higher than it was a decade ago," he said.
"Whatever the statistical debates, it is absolutely clear that we have deep-rooted problems that just have to be tackled."
But Home Secretary Alan Johnson said the Tory figures were "concocted" and more reliable figures showed overall crime levels were down a third since 1997 while violent crime had fallen by 40%.
"The Tories have consistently said there has been a 70% increase in violent crime," he said. "We can't put up with this any longer."
Asked about a Labour film claiming that a burglar was more likely to vote Conservative at the election, Mr Johnson said this was justified as the Tories' voting record on crime and their policies did not match their "tough rhetoric" on the issue.
The Conservatives responded by saying Labour's decision to release 80,000 prisoners before the end of their jail term - some of whom went on to commit serious crimes - demonstrated Labour was "soft" on crime.
The BBC's Home Affairs Editor Mark Easton said the Conservatives were having to rethink their pre-election message on crime after a reprimand by the statistics watchdog last month.
The UK Statistics Authority criticised Mr Grayling for "misrepresenting data" on crime figures, after he compared levels of violent crime recorded by police in recent years to those before 2002.
The watchdog insists such comparisons are unreliable since the police changed the way they recorded crime in 2002.
It says the British Crime Survey - which has interviewed people about their experience of crime since 1982 - is a more reliable measure of long-term crime trends since it covers crimes not reported to the police.
But critics of the survey - which suggests peoples' experience of violent crime has fallen since 1997 - say it does not tell the full story as it does not reflect local variations and only records crimes in private homes.
The watchdog, which has also criticised Labour for its use of statistics in the past, has published correspondence with Mr Grayling in which it recommended he take advice from the House of Commons officials on using "reliable methodology" for crime figures.
However, it also advised against "selective quotations" from individual reports that could prove "misleading".