Goldmine in your backyard? Expert questions 100,000 new home Auckland estimate

A new report estimates 100,000 homes can be built on existing Auckland sites but one expert has questioned that number.

Homes.co.nz cites the potential to subdivide existing Auckland sections to create another 100,000 houses, saying many of the city homeowners could have a potential goldmine in their back yards.

But Bryan Thomson - who today was announced as Harcourts' new managing director in New Zealand from April - questioned that 100,000 figure.

"How many sections can you practically subdivide when you look at sizes, shapes, slopes, location? I'm not disagreeing with the statistics but the question is that just because a piece of land is large enough to be subdivided, is it practical to do so, even if it's allowed under the Unitary Plan?" Thomson asked.

"There are properties where subdivision does make sense but it's not that simple," said Thomson, currently the principal of consultancy Bryan Thomson Associates.

Aidan Jury of Jennian Homes has cited the high value of land and construction costs.

The report said that across the city, 85,000 existing properties could be subdivided to become smaller than they currently are, carving off at least one other section in the process.

That would create 109,775 new properties, equal to an additional 20 per cent of Auckland's housing stock.

One of New Zealand's largest house-builders, G.J. Gardner, has long run a marketing campaign tagged 'green is the new gold' and encouraging home owners to build new places.

Many existing homes are cold, damp or even leaky, "sitting on large sections in desirable suburbs, close to popular centres. Very frequently this poor quality undercapitalises values, or perhaps the time-consuming lawn is the key to financial freedom and early retirement," the house builder says.

Owen Vaughan, editor of OneRoof, said some Aucklanders with larger sections could "cash in on the ground beneath their feet, with duplexes an option for those who do not think they have the land to support separate townhouses."

Intensification of the city did not necessarily mean building more apartment tower blocks, Vaughan said, but well-designed townhouses and "accessory dwellings" were alternatives.