Aerial drones will help in the potentially hazardous demolition of earthquake damaged homes in Christchurch's Port Hills.
The Canterbury Earthquake Recovery Authority says the demolition of properties prone to rockfall and cliff collapse is due to begin on Monday.
The authority says the job will be complex and challenging. Large water blasters and controlled explosives will be among a variety of tools used, while the drones will take images of the sites.
Chief executive Roger Sutton says freight containers will be used to create safe zones for the workers, escape routes will be identified and spotters will watch for any signs of rockfall.
More complex demolitions will take up to a year of planning before work is carried out, he says.