Home Secretary John Reid will hold an urgent meeting over reports that details of serious overseas offences were ignored by the Home Office.
"This is a very serious problem and I take it very seriously indeed," Mr Reid said on Tuesday night.
British criminals may have been cleared to work with vulnerable people in the UK after committing serious crimes abroad, police chiefs have said.
Some 525 British criminals may have applied for jobs back in the UK.
'Called in police'
The Association of Chief Police Officers says details of 27,529 cases, including 25 Britons convicted of rape, were left in files at the Home Office.
Acpo said they should have been entered on the Police National Computer (PNC).
Mr Reid said: "I've called in the police and the Criminal Records Bureau tomorrow morning for an urgent meeting and I want to establish the facts and satisfy myself that everything has been done to protect the public."
The Home Office said earlier that an inquiry had begun and that most serious offenders have now been added to the PNC.
Responsibility for updating the records was transferred from the Home Office to Acpo last year.
The cases involved included:
25 rapes3 attempted rapes29 paedophiles17 other sex offenders5 murders9 attempted murders13 manslaughter convictions29 robberies
Acpo spokesman Paul Kernaghan told the Commons all-party home affairs select committee that the position was "totally unacceptable" in terms of protecting the public.
Mr Kernaghan, who is Hampshire's chief constable, said: "Until the Acpo criminal records office was created, someone could go to Germany, commit a sexual offence and serve a sentence - and this would not be known to any police officer when they came back to the UK."
He added: "The information was sitting in desk files and not entered on the [Police National Computer].
"That is now being addressed and they are working their way through putting serious offenders on a risk-assessed basis on the PNC."
Acpo said none of the rapists had been subject to the sex offenders register, and that employment checks on the Criminal Records Bureau (CRB) would have found no trace.
The CRB is investigating whether serious offenders in 525 cases have applied for jobs.
Responsibilities were transferred from the Home Office's UK Central Authority for Mutual Legal Assistance to Acpo's UK Central Authority for the Exchange of Criminal Records on 21 May 2006.
Shadow home secretary David Davis said: "Of itself this is disgraceful but it is by no means the first of the government's systems which have had major failures in the past few years - whether it is the Police National Computer, the Criminal Records Bureau or the Sex Offender Register.
He added: "The Home Office has got to learn to walk before it can run, to get the basics right. Any other approach just puts the public at risk."
Liberal Democrat home affairs spokesman Nick Clegg said he would be tabling an urgent question in Parliament.
He said: "This blunder not only exposes this government's administrative incompetence, it puts the British public at greater risk from these offenders."
Home Office minister Joan Ryan told BBC News the department was doing its best to deal with the situation.
She said: "These matters, as far as we know, were unknown to the home secretary or any of the current ministers until some time just after lunchtime today.
"So we have moved very quickly to deal with what we acknowledge is a most serious situation."