Some earthquake-damaged buildings can't come down quick enough as "foolish" graffiti artists are pushing the limits to spray their tags.
Vandals have scaled some of the city's biggest landmarks, including the dilapidated AMI Stadium, the old brick railway station on Moorhouse Ave, and the Canterbury Brewery building, to leave their mark.
They've scaled security fences and demolition machinery, beaten security measures and denied gravity to spray their distinctive signatures.
But police are concerned that the practice will end in tragedy and have urged them to stay away.
"They're putting themselves at risk, and more importantly, others who have to extract them if things go horribly wrong," said central tactical co-ordinator Senior Sergeant Glenn Nalder.