Labour leader Phil Goff says police intelligence has been seriously compromised after a confidential document was left at a gang house raided by the police.
The report was left at a state house in Pomare, in Lower Hutt, which was occupied by the Mongrel Mob. The house was raided on 11 February as part of a Housing New Zealand eviction process.
It detailed which officers were carrying weapons, and what types, as well as where they were deployed.
Mr Goff says this is sensitive information in the hands of the wrong people.
Police Minister Judith Collins also wants answers about how this happened. She is expected to meet Police Commissioner Howard Broad about the incident.