The Christchurch City Council says it will take up to 15 months to complete earthworks designed to protect 21 Port Hills homes from the threat of landslides.
The land has been made unstable by the ongoing earthquakes over the past four years.
Sixteen properties are beyond saving and will be purchased by the council.
The council geotechnical engineer, Ian Wright, said there were two types of work that were going to be carried out to prevent further landslides.
"The ideal solution is to bench it, a series of cut benches or cut the slope back. If we can't do that because of accessibility, we would look at a secondary way in terms of retaining walls."
Mr Wright said where landslides could not be prevented, a bund would be built to stop soil and rocks from reaching homes.