Professionals Pt Chevalier branch manager Ross Brader told the Weekend Herald this year's revision was completely random. The extent of miscalculations was much worse than in previous years, forcing vendors to fork out for independent valuations before putting homes on the market.
"Some properties have sold for hundreds of thousands below [CV] and hundreds of thousands above."
A renovated three-bedroom ex-state house on Pt Chevalier Rd is worth $550,000 according to its CV notice. The property was appraised at $920,000 last week and is expected to sell for about $900,000 - nearly twice its council estimate.
An Old Mill Rd home in Westmere has just sold for $1.225 million - 21 per cent below its new CV, while a property in Pt Chevalier went for $700,000 below.
Mr Brader said the council estimates were often wildly out and real estate agents usually considered them irrelevant. But many lay people relied on them as an official figure, particularly new immigrants.
"My personal view is they should come up with a new system because it's just a complete waste of time."
Kellands reality agent Martin Dobson sold the four-bedroom Waiheke clifftop property last week for nearly three times its $810,000 council valuation. He had no idea why the new CV was so low.
Sheldons valuation company director Gary Brunsdon had been inundated by homeowners concerned about their properties' newly calculated CVs.
Many wanted an independent valuation, which involved an inspection and appraisal of features, refurbishments and aspects which could influence the sale price. They cost $500 to $600, or up to $1500 for a high-spec property.
He warned that council CVs were based on "mass appraisal computer-generated estimates" that were calculated sight unseen by council officials for the purpose of setting rates.
Auckland Council revaluations manager Mindy James defended the system as "fair, equitable and robust".
Valuations were set according to recent sales in relevant geographical areas and took into account any changes to the property since the 2011 revaluations such as consented work, zoning changes and subdivision.
Valuers carried out some form of physical inspection on most residential property sales that occurred in the six months to July 1 to check what was actually sold and update their records.