Billionaire Graeme Hart's clifftop mansion is among luxury homes, schools, churches and golf clubs being set aside for possible infill housing and apartments in a new planning rulebook for Auckland.
Schools, including Kings Prep in Remuera and De La Salle College in Mangere, were unlikely to be replaced by houses, said council chief planning officer Dr Roger Blakeley, but it was still a possibility.
Dr Blakeley was commenting on a stocktake of land and property in the existing urban area that pinpoints large parcels of land that could be subdivided for infill housing and apartments.
As well as schools, the stocktake has captured resthomes, churches and the Grange Golf Club in Papatoetoe.
Luxury homes on large sections in Remuera and the eastern suburbs could also be replaced with more intensive housing.
Schools and other properties have been labelled "residential vacant" (vacant land) and "residential vacant potential and infill" (land with some buildings) in a council report, with capacity for housing development.
The report, Capacity for Growth Study 2012, looks at how many new dwellings could be built in urban Auckland under the existing district and regional plans.
The rules vary between the old councils, but generally limit suburban areas to standalone houses and limit intensive housing to business and mixed-use land.
The report has arrived at a figure of 189,059 through infill housing and 273,045 through infill and other forms of development, such as apartment blocks.
Dr Blakeley said this was the maximum theoretical capacity.
Given the reality was about half that figure, he said, new tools were needed in the new rulebook - or Unitary Plan - to achieve the goal of 280,000 new dwellings in urban Auckland over 30 years.
The rulebook includes far more intensive housing in suburban areas, including apartments, and a mixed housing zone, that has no density limits - subject to certain controls - when developers landbank more than 1200sq m.
A review of the report by Patrick Fontein, of Studio D4, for the Property Council, said the council overstated the actual development sites by including schools, churches, retirement villages and some parks.
It also took insufficient account of sloping sites, cliff-top sites, sites in valleys and sites prone to flooding.
The review looked at the Orakei and Otara-Papatoetoe Local Board areas and identified the 10 largest "residential vacant" and "residential vacant potential and infill" development sites in each area.
In previous work for the council, Mr Fontein found that without major rezoning only 45,000 to 60,000 dwellings could be built in urban Auckland over the next 30 years, but with upzoning and strong political leadership there was a capacity for 270,000 new dwellings.