Christchurch Mayor Bob Parker has warned owners of historic quake damaged buildings not to start demolition work without prior consent from the council.

It was important that owners worked with the council so as many historic buildings could be preserved as possible, Mr Parker said.

"While public safety remains paramount, I would encourage owners of damaged heritage listed buildings and character buildings to work with the council so that we can do what we can to preserve these buildings, which are so important to the character of our city," Mr Parker said.

Owners of all damaged buildings needed to get permission from the council to ensure gas, power and water services had been disconnected before demolition went ahead, Mr Parker said.

Owners of any buildings who started demolitions without notification put public safety at risk and could cause damage to adjacent buildings, he said.

People also needed to be aware that a red sticker only meant a building could not be entered and did not give owners permission to knock it down.

Christchurch City Council would severely punish any owners who did not notify the council, Mr Parker said.

"The council will take strong regulatory action against any owners who demolish buildings contrary to these requirements," he said.

Permission to demolish buildings would only be granted following assessment by at least two structural engineers and owners needed to supply a plan with options for the building to inform the decision process, Mr Parker said.