A report on rising sea levels is urging the Christchurch City Council to prepare the South Island city for the prospect of some of its coastal areas being under water within 100 years.
The report by environmental and engineering consultancy Tonkin and Taylor predicts that Sumner, New Brighton, South Shore and Brooklands will be among the areas flooded by the rising sea.
It says predicted levels have doubled since a report in 1999.
The report says the council may have to plan for the abandonment of properties, because it will be too expensive to protect all areas vulnerable to flooding.
Recommendations made to the council include developing an adaptation strategy for ensuring that all future studies involving tsunamis and erosion take into account the effect of sea levels.
Deputy mayor Vicki Buck said on Wednesday the council is taking the report into consideration.
"The report is incredibly timely and the reason for the review was that there is a district plan review about to be undertaken this year.
"So obviously, it's important that we address all of these things sensibly and logically now, rather than leaving them. That will mean a great deal of community engagement with those areas that are affected."
Christchurch is rebuilding itself after a devastating earthquake in February 2011.