The Christchurch City Council has signed a contract with Hawkins Construction to carry out the $127 million repair of the city's town hall.
The iconic building, opened in 1972 and designed by architects Warren and Mahoney, was badly damaged in the 2011 earthquakes.
The insurance payout covers less than half of the cost of the repairs, making the project one of the most expensive undertaken by the council as part of the rebuild.
Mayor Lianne Dalziel said, when dealing with a category one heritage building such as the town hall, the correct place to start was working out whether it could be repaired.
She said the business case for the repair work stacked up, making it the best thing emotionally and financially for the city.
Ms Dalziel said the building would be strengthened to 100 percent of the building code.