Building and Housing Minister Nick Smith said properties might be vacant because of owners being on holiday, renovating, selling or tenants coming and going, but Labour housing spokesman Phil Twyford says "ghost housing" is a huge issue in Auckland and he is concerned about the effects.
Auckland's most high-profile empty mansion is the Spanish-style, turret-topped Herne Bay house at 81 Sarsfield St, which is thought to be worth about $15 million. It has stood empty for years and is now being demolished.
The Herald reported last October that the house dubbed "Circus McGurkus" would be demolished and replaced by a new building this December.
In Auckland, Watercare cannot supply data on low-use properties.
"Our water use data is held within our billing system, which is set up to enable us to support our customers by identifying unusually high water usage. Unfortunately, our system has not been set up to identify customers that use no water," said a spokeswoman.
"We don't have that information. Our focus is on potential leaks and notifying customers of high usage ... Collecting data regarding low usage is not necessary."
Nor can electricity providers give figures. A spokesman for one of the major suppliers said disconnections did not necessary mean dwellings were vacant but instead could indicate a customer had shifted to another provider.
In Canada and Australia, ghost housing estates are a big issue.
An analysis this year by the University of Sydney's City Futures Research Centre examined reasons for about 90,000 Sydney properties being vacant. It found "perverse" tax incentives encouraged investors to leave the homes empty in the most desirable suburbs, adding fuel to the housing affordability crisis.
A similar study in Melbourne last year analysed water use and suggested more than 80,000 properties, or 4.8 per cent of the city's housing stock, appeared to be unused.
In Canada, the Vancouver Sun has reported this year how one in 10 condos were empty.
Empty nests
Auckland
509,625 dwellings
33,360 unoccupied dwellings
New Zealand
1,561,959 dwellings
185,445 unoccupied dwellings
Australia
Sydney
90,000 residences vacant
Melbourne
80,000 residences vacant
Sources: Census 2013, City Futures Research Centre