The former Arrowtown borough council building is the first stone heritage building to undergo earthquake-strengthening for preservation and public safety in the township.
Scaffolding adorns the exterior of the privately-owned building, in the same row as the gold miners' cottages in Buckingham St.
Cook Brothers Construction business development director Simon Glass, of Queenstown, said the $35,000 week-long project involved installing a steel structure around the interior of the perimeter walls, fixed to the blocked-off chimney cavity.
A dozen galvanised rods through drilled holes will secure the facade. All new steel will be tidied under a concrete parapet cap, which will be plastered and painted to blend in with the building.
Mr Glass said the Dunedin-headquartered construction company was beginning to pick up more earthquake-strengthening contracts and had worked in the Jade Factory, Arrowtown, and in the historic Bank of New Zealand building in Princes St, Dunedin.
The borough council building was originally and briefly a Masonic lodge when it was built in the mid-1870s.
It then became council chambers until 1989 when borough and county councils were amalgamated into larger districts.
Records in the Lakes District Museum, Arrowtown, reveal the building became the village's first medical centre in the late 1980s, then an engineering firm's office.
It is now a health spa.
