The caution comes as the council begins an investigation into the removal of slate tiles from the roof of a New Zealand Historic Places Trust category 2 building in Dundas St.
The building was part of the terrace houses in Dundas St, built in the 1880s.
The tiles were replaced with corrugated roofing iron on Tuesday, attracting three complaints from the public to the council.
House owner, All Black and Highlander lock Tom Donnelly said the work had become necessary after the roof developed severe leaks and the tiles began to fall through the ceiling.
Any work which replaces or alters the outside of a historic building needs resource consent.
Council resource consents manager Alan Worthington said Mr Donnelly had not gained the appropriate consent.
"It's something that needs to be addressed."
Mr Worthington said the situation would be investigated, and Mr Donnelly could be asked to get a resource consent after the fact, and he could also be asked to remove the roofing iron and replace it with slate tiles similar to those removed on Tuesday.
Mr Worthington advised anyone intending to make alterations to their house to call the DCC planning desk, where information about the necessary consents could be found.
"This isn't just for historic buildings, it's for any buildings."
Under the Resource Management Act, the owner of a building could be fined hundreds of thousands of dollars or imprisoned for breaches of resource consent, he said.
"But the incident on Dundas St is nowhere near in that league of offence. People just need to be careful," he said.
"Ignorance is no defence."
New Zealand Historic Places Trust Otago Southland area manager Owen Graham said the trust worked closely with the council to educate the owners of historic buildings.
The trust held volumes of information on how owners could make alterations to their buildings without destroying character, and he encouraged owners of historic buildings to contact the trust.
