Dunedin City Council property manager Robert Clark said yesterday there would be a cost to the work, although it would fit within contingency budgets included in the project's financing.
Work on the $5 million renovation of the Municipal Chambers began in July last year, part of the wider Dunedin Centre and town hall upgrade originally priced at $45.8 million.
That figure should decrease because in April, Mr Clark noted in a report, savings of between $3 million and $4 million had been found following a review of the Dunedin Centre upgrade, and changes to its scope.
The control group for the project was undertaking a similar review for the town hall, to find more savings. Mr Clark said this was under way.
It was also noted at the time that "unplanned but necessary" work had slowed the redevelopment, though a June 30 date was listed for scheduled completion.
Yesterday, Mr Clark said the work would take another month.
"It's not finished, the reason being that we have had to do some extra work in the council chambers regarding fire, and replacing lights."
He said "down lights" in the room were sunk into the ceiling in small wooden surrounds, and those showed signs of heat damage.
"We had to replace all of those, and shift them.
"It is something you have to watch in all properties.
"People put insulation on top of them, and they do generate some heat. The discovery meant workers had to "redecorate totally".
Mr Clark said the building was historic, and work had to be done "correctly".
"We have to be careful from a Historic Places Trust point of view.
"Also, we're replacing the carpet, and we're waiting for the carpet to arrive."
With such a large project, such issues were expected, and contingency funding was in place for that reason.
The other outcome of the delay was the council would have to have its meetings in the Dunedin Public Art Gallery, as it did on Monday, until early August.
Councillors would be briefed on the issues in the next month.
