Police are investigating the "disappearance" of an officer's notebook which was copied and circulated, disclosing personal information of victims and offenders.

The Herald was sent copies of pages from the book.

Police have confirmed it went missing in Dunedin in August during the execution of a search warrant.

An unsigned, anonymous letter accompanying the pages said police did not want the public to know the notebook was missing as it contained private information.

The notebook has now been recovered.