The Christchurch City Council is working to identify how many of its properties could be contaminated with toxic substances.
The Canterbury Regional Council has detailed 316 city council properties where the soil could be contaminated because of their past use.
These could include former landfill sites or areas where chemicals have been buried.
The city council's property analyst, Tim Priddy, said each property would be profiled to identify its past and current use before being ranked in terms of priority for further investigation.
Many of the properties are cemeteries, parks, reserves and sportsfields, but some housing complexes, playgrounds and picnic areas are also under the spotlight.
They have been identified as properties that could be sitting on former landfill sites, or areas where chemicals have been buried.
Mr Priddy said the next stage of work would involve specialist consultants testing sites, with the results made public.