A drilling rig has been operating this week in Harrop St and the Octagon, digging two 30m deep bore holes to collect samples.
The Dunedin City Council said geotechnical investigative work was part of a structural assessment of the central city complex, which requires restorative work.
The samples would "help create digital models and assess the durability of the buildings in different earthquake scenarios using virtual computer simulations".
Geotechnical work could be completed tomorrow.
Construction of the Municipal Chambers, a category 1 heritage building, was completed in 1880.
The category 2 Town Hall opened in 1930.
The full restoration programme is forecast to be completed in 2028.
It involves restoration of four rooftop pavilions, the clock tower and roof and intricate work on the building’s exterior.
More work may be needed to strengthen the building structure.
The focus of restorative work will shift to the Glenroy Auditorium and Town Hall once the Municipal Chambers work is finished. — APL
