Christchurch City Council says it is acting in the public interest by using a private investigator to prove some home owners are living in homes which have been red-stickered.
Council regulation and democracy manager Peter Mitchell says an investigator has been engaged for a number of months to monitor about 15 out of the 500 homes in the Port Hills area that are red-stickered.
Mr Mitchell says, while residents are allowed to visit the homes, they are not allowed to live in them.
He says the council is concerned about the risk some people are posing to themselves and others by ignoring the warnings.
Mr Mitchell says the information being gathered will be used as evidence should a case be taken to court.
