The government is assessing the impact of a "technical issue" that led to 150,000 records being deleted from police databases.
The error, first reported in the Times, saw data including fingerprint, DNA and arrest histories wiped after being accidentally flagged for deletion.
The Home Office said the lost entries related to people who were arrested and then released without further action.
But Labour said it presented "huge dangers" for public safety.
The data was lost from the Police National Computer - a system that stores and shares criminal records information across the UK.
It is used to help police investigations and provides real-time checks on people, vehicles and crimes, as well as whether suspects are wanted for any unsolved offences.
A coding error resulted in records that had been flagged for deletion being lost from the database before checks had been carried out to determine whether they could be lawfully held or not.
The data loss could hinder future police investigations because the fingerprint or DNA evidence would not be able to be cross-checked against evidence from other crime scenes.
Policing minister Kit Malthouse said the problem had been identified and the process corrected so "it cannot happen again" - with the Home Office, National Police Chiefs' Council and other law enforcement partners working "at pace" to recover the data.
"While the loss relates to individuals who were arrested and then released with no further action, I have asked officials and the police to confirm their initial assessment that there is no threat to public safety," he said.
The Home Office said no records of criminal or dangerous persons had been deleted.
The records are linked to police investigations that were terminated before charge (No Further Action or NFA cases) or to those where an individual had been acquitted at court.
It is not yet known how many records of each type were lost and full extent of deletions is still being investigated.
The loss of the data means that officers on the ground may get an incomplete search result when interrogating the system.
'Answers are needed'
Shadow home secretary Nick Thomas-Symonds called on Home Secretary Priti Patel to take responsibility for the error and be clear about the impact it had had.
"She must urgently make a statement about what has gone wrong, the extent of the issue, and what action is being taken to reassure the public. Answers must be given."
"This is an extraordinarily serious security breach that presents huge dangers for public safety."
Former Cumbria Police chief constable Stuart Hyde told BBC Radio 4's Today programme the "very large" loss of arrest records presented a "risk to public safety".
He said: "In order to understand the scale, if you think that about between 6-700,000 people are arrested every year in the UK, that's a very large proportion of those people."
It comes after around 40,000 alerts relating to European criminals were removed from the same database, the PNC, following Britain's post-Brexit deal with the EU.
- LOCKDOWN LEARNING ON BBC IPLAYER: BBC Bitesize is here to help with your homeschooling needs
- IN NEED OF A NEW SERIES TO BINGE IN LOCKDOWN?: The Serpent is a twisting, real-life story of a murderer, thief and seductive master of disguise