Scaffolding surrounds the roof of the Dunedin Centre, which Dunedin City Council city property manager Robert Clark said was part of work to incorporate air conditioning, plant and ventilation.
On the St Paul's Cathedral side of the building, contractors are building an extension on to a roof area outside the Fullwood Room, on the third floor of the Dunedin Centre.
What was formerly an unused roof space would become an outdoor function area, Mr Clark said.
The windows, which are beside that space, had been covered up to keep light out of the town hall for daytime shows, but the plan was to redesign the area so they could be opened or closed when necessary.
The windows have been blacked out for as long as most people can remember, possibly going back to World War 2.
The windows on both sides of the town hall were uncovered during 1986-87 renovation of the former Concert Chamber, but covered shortly after to keep the light out.
Mr Clark said the blue tarpaulins now covering the windows would be removed, and the windows could become "a feature".
The contract for the work was expected to be completed by December 15, next year, and the buildings opened in early February 2013.
