The break-in took place at Hazel Blears Salford office on 14 June
Information on a computer stolen from Communities Secretary Hazel Blears' office had been sent in breach of data security rules, it has emerged.
The Communities and Local Government department admitted its officials had "not fully" complied with guidance on handling sensitive data.
Its top civil servant Peter Housden said "no damage had been done" as the documents were not secret.
Manchester Police are investigating the theft from Ms Blears' Salford office.
The computer contained a combination of constituency and government information relating to defence and extremism.
Mr Housden said in a statement: "It is clear that papers have been sent to Hazel Blears in a way that is not fully consistent with the departmental guidance.
"Thankfully no damage has been done since the documents sent to her were not classified as secret or top secret. And in any event the computer was password protected.
"I have instructed my officials that departmental procedures, guidance, and the awareness and accessibility of that guidance, are now strengthened to ensure this does not happen again.
"I take full responsibility for ensuring this is done."
Department sources suggested that no officials were likely to lose their job over the breach, but did not rule out disciplinary action.
This is the latest in a series of security breaches that have embarrassed the government. Last week a senior Cabinet Office official was suspended for leaving top secret documents on a train.
Another file of documents, including one restricted one, was found on another train last week as well.
After Gordon Brown was informed of the theft from Ms Blears' office, he told cabinet ministers to ask their civil servants to remind staff of the importance of enforcing procedures on the treatment of sensitive information.
Shadow home secretary Dominic Grieve called for Parliament to be told "exactly how and why this has occurred".
"The news that a government minister may have been directly responsible for the loss of data relating to extremism is extremely alarming," he said.
The stolen computer is understood to have contained one confidential document relating to the housing market from March this year, as well as other restricted documents.
But the documents did not contain any information that could compromise national security.
They also contained information that shows Cabinet members disagree over the government's proposed planning laws.
Restricted government documents should not be held on a personal computer.
A government spokesman said the machine contained material from the Department for Communities and Local Government and details relating to her constituency work.
He insisted no personal details were among the departmental information.
"There was a break-in at the constituency office of Hazel Blears on the afternoon of Saturday, 14 June. Hazel was not there at the time, " the spokesman said.
"The thief broke in through a window, triggering the building's security alarm. A PC was stolen. Nothing else was taken.
"We understand the building's security staff arrived within minutes.
"The PC was primarily used for Hazel's constituency business and contained some details of her constituency work."
The spokesman said "none of the departmental material included sensitive personal data about the public or would be of use to criminals".
He added: "The PC did not contain any secret or top secret information and the contents of the PC are protected and clearly this is now subject to a routine police investigation."