Christchurch mayor Bob Parker has told building owners they face hefty penalties if they demolish character buildings without consent.
A building recovery office will be opened on Monday to consider applications for damaged buildings to be pulled down.
Mr Parker says he has heard stories that at least some old character buildings have been torn down without a consent.
However, he warns that all demolitions must be permitted and building owners will have to satisfy a specialist heritage team that a building is not repairable.
Mr Parker says 81 buildings in the CBD have red stickers, indicating they are not considered safe to go into.
But he says many of them may not be as badly damaged as initially thought.
Mr Parker says a special fund is being set up to help owners to repair borderline buildings considered of heritage or character value.
He says a group of heritage experts has been set up to advise on the practicalities - or not - of retaining buildings.
There is a briefing on Monday at 7pm at the James Hay Theatre for owners of historic buildings, to hear from the council and perhaps from heritage experts.
Court Theatre
The Christchurch Court Theatre intends to have its shows back on the stage within weeks, with its historic building sustaining only minor damage.
The theatre is located in the old University of Canterbury buildings, which now make up the Christchurch Arts Centre.
The theatre's artistic director, Ross Gumbley, says while some areas of the building have had minor problems, the theatre is in the same condition it was before the quake.
He says it will reopen when engineers have finished inspecting the building.
