The Information Commissioner has called on the Government to introduce tougher penalties for people involved in the "dirty trade" in personal information.
On Monday the Home Affairs Select Committee is set to publish a controversial list of clients of rogue private detectives, featuring law firms, insurance companies, financial services groups and celebrities.
But the commissioner, Christopher Graham, said MPs should not be focused on "a day's headlines" and instead demanded that ministers implement effective regulatory action.
The names of around 100 firms and individuals who allegedly used corrupt private investigators was handed from the Serious Organised Crime Agency (Soca) to the committee earlier this year on condition it was not published - sparking a row over transparency.
Trevor Pearce, director general of Soca, refused to release the document despite an ultimatum from MPs and committee chairman Keith Vaz. Mr Vaz told Mr Pearce and Stephen Rimmer, Soca's interim chairman, the committee would publish the list on Monday if Soca did not do so first.
Writing in a blog, Mr Graham said: "It's not clever to start a criminal investigation by publishing the names of everyone and everything you're investigating. That's why we've stated we're not publishing the list at this stage, and why I've written to Keith Vaz MP to urge similar patience on the part of his Select Committee."
He went on: "For years we've been warning about the dirty trade in confidential personal information and the threat to our privacy and security posed by the blagging of personal information in family disputes, in the insurance business, in the credit sector - and for purposes of fraud and other criminal enterprises."
Mr Graham stated that blagging cases were "all too often" dealt with at magistrates' courts where the punishment was just "a slap on the wrist of around £150".
He added: "Keith Vaz and his Select Committee continue to focus on whether the private investigator client list should be published. But surely effective regulatory action is what is needed, rather than a day's headlines. If MPs really want to do something to stop the blagging they should demand that ministers stop shilly shallying and implement the tougher penalties that recognise the blagging problem for the scourge that it is."
The Information Commissioner's Office last week announced its own investigation into nearly 100 of the private eyes' clients.