Ministers have been accused of "gagging" MPs in a row over terrorists and other dangerous criminals being released from prison.
Justice minister Maria Eagle wrote to MPs this month offering to tell them about serious violent and sexual offenders and convicted terrorists who are released in to their communities.
But they will only be given the information - including the names of the individuals - if they agree not to tell the public, and the Tories said MPs are being forced to choose between being kept in the dark and not being able to tell their constituents.
Shadow justice secretary Dominic Grieve said: "Managing the release of serious offenders is a difficult issue but the Government is trying to impose a blanket gag on MPs doing their job, in return for being kept informed of dangerous offenders released into their constituencies.
"The scheme is unenforceable, but it is still surprising that ministers would expand it in this way, without advance consultation or thinking through the implications.
"At a time when the Government is releasing thousands of dangerous offenders early - having undermined the probation service's ability to supervise them properly - this measure will only further weaken public confidence."
But the Ministry of Justice said widespread releasing of information about offenders could undermine public safety.
A spokesman said: "MPs should not disclose specific details of the whereabouts and identities of individual offenders because doing so would compromise their management in the community and, ultimately, the safety of the public.
"We have greatly extended openness and are committed to providing communities with more information about the justice system.
"However it is also the case that fine judgments need to be made in the management of offenders - for the protection of the public, which is our guiding motivation."
