A report claiming Napier and Wairoa councils have under-invested in vital infrastructure was partly based on financial information flagged as "deceiving" by independent consultants who compiled it for the Local Government Commission.
The consulting firm says despite inconsistencies in the information it collected, it is confident it provided the commission with an accurate "overall picture" of the financial state of Hawke's Bay's councils.
The report has outraged Napier City Council which disputes the commission's claim that Napier ratepayers would need to spend tens of millions of dollars catching up on the city's spending on roads and water systems compared to other parts of the region.
The five-page report, released by the commission on Friday, said Napier and Wairoa had less total debt, and more financial assets, than the Hastings and Central Hawke's Bay district councils.
"Put simply, improving Napier City Council's infrastructural assets to have the same residual life as the average across the region would require all of Napier's $78.6 million of net financial assets and a further $45 million. In contrast, Hastings' infrastructure assets have a longer residual life than the regional average," the commission said in its report.
The report's conclusions are based on data taken from a study it commissioned from consulting firm MWH New Zealand.
The study also says while Napier City Council commissioned a detailed independent review of its infrastructure last year, similar studies "would have to be carried out for all councils before a more complete and accurate comparison of the infrastructure asset management situation in Hawke's Bay could be made".
Some "quite significant inconsistencies" were identified between the study's information sources, MWH said.
"A more comprehensive exercise may change the degree of some of the conclusions reached but not the overall picture."
MWH senior consultant Andrew Maughan declined to comment on the issue of the "deceiving" data yesterday, referring questions about the study to the commission.
A commission spokeswoman said because the question was about a technical aspect of the report, it could not be answered until it was discussed with the appropriate commission staff and MWH.
Napier Mayor Bill Dalton said he would make "a strong call" for the information released by the commission on Friday to be independently reviewed.
"Failure to have the information independently reviewed would further demonstrate a pre-determined position by the LGC," he said.
Napier City Council chief executive Wayne Jack said the commission had taken selected information from the MWH study and also used outdated information from the council's long-term plan.
"It's very clear that what the commission has done is written a report to try to achieve the outcome they wanted."
The council plans to provide a detailed response to the commission's report this week.
Hastings Mayor Lawrence Yule said on Friday the new report enabled the region to "put debt and long term infrastructure costs in context".
"Simply put, debt is not an issue as Hastings District Council has quality infrastructure that is well maintained and funded and most importantly has significant residual life. This residual life is already funded and not a future liability," Mr Yule said.