Work is beginning to bring down the 21-storey PriceWaterhouseCoopers building in the largest demolition job following the February earthquake.
The owners of the 22-year-old building on Armagh Street in central Christchurch have decided it is not feasible to repair the damage it suffered.
The Canterbury Earthquake Recovery Authority says the building is not the tallest in Christchurch but is the largest by land mass.
The demolition is expected to take 40 weeks to complete.
The first stage will involve stripping out the 21 floors.