Coastal flooding and erosion information should be removed from thousands of Christchurch property records, a panel of scientific experts says.
It found maps used to identify at risk properties in the city could be "legally unsound" and should be put to one side until new ones are completed.
The view has been applauded by the Christchurch Coastal Residents United (CCRU) group, which now hopes the Christchurch City Council will remove the information.
CCRU has been fighting to get the information taken off Land Information Memorandum (LIM) reports since they were changed last year to reflect the potential risk of flooding or erosion as identified in a controversial Tonkin & Taylor report.
Residents questioned the science behind the report and were concerned the LIM notations would affect property values and future insurance coverage.
The Tonkin & Taylor report, released in July 2015, identified 6000 Christchurch properties that could be susceptible to erosion and nearly 18,000 at risk of coastal inundation over the next 50 to 100 years.
The council decided in December to subject the report to a second peer review by a panel of scientific experts. The panel's final report has been released and will be discussed by the council on Thursday. However, the council was not expected to decide until next month whether to amend the LIMs.
The panel has highlighted a number of aspects of the Tonkin & Taylor document that need to be changed or re-assessed. It has recommended maps highlighting coastal erosion hazard zones be discarded and redone for harbour areas including the Avon-Heathcote Estuary and the Akaroa and Lyttelton harbours. Maps from Waimairi Beach to Southshore should also be revised before they were used for planning purposes.
The panel considered the overall Tonkin & Taylor report to be fit for purpose, but only once those changes had been made. The council asked the panel to suggest ways forward and those moves included removing the maps from LIMs.
The Tonkin & Taylor report was completed in a "tight timeframe with limited budget", the panel said. The company was given 20 days to complete the report.
"In these circumstances, to meet time and budget constraints, simplifying assumptions can be expected," the panel said.
CCRU spokesman Darrell Latham said the panel had vindicated CCRU's call for due process and fair procedure.
"The report should not have been used for planning purposes," he said.
"It was not a sufficiently robust document nor was it fit for that purpose, hence the panel's many recommendations for additional work to be done."
CCRU chairman Tim Sintes said the community, council and experts now needed to work together to measure what was actually happening locally and plan how to adapt as sea levels change.
"Christchurch and coastal residents deserve nothing less."
The panel experts include retired Environment Court judge Shonagh Kenderdine, New South Wales University coastal engineer Ron Cox, Canterbury University coastal studies senior lecturer Dr Deirdre Hart, Waikato University earth sciences senior lecturer Dr Willem de Lange and statistician Dr Murray Smith.
What is a LIM?
A Land Information Memorandum (LIM) contains all the information a council holds on a property. It includes rates and water charges, lists of building permits and consents, information on protected buildings and trees, historic buildings, special characteristics of the land or buildings, resource consents issued within 100 metres, drainage information relating to sewer and stormwater and any available earthquake-related information. People planning to buy, sell or develop a property can request a LIM from their local council.